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Objective: To estimate the effectiveness of several vaccine brands-Pfizer, Astra, and Sinovac-against symptomatic COVID-19 without information on vaccination at the individual level., Methods: We use data of mass vaccination programs-specifically, for sexagenarians and quinquagenarians-in three large municipalities of Mexico (Monterrey, Guadalupe, and San Nicolás) to conduct a two-step time series estimation procedure involving a synthetic control group. The data covers the period between the first week of March 2020 and the first week of October 2021., Results: Vaccine effectiveness is a concave function of time. At the peak, Pfizer reaches 92.6 % effectiveness, Astra 83.6 % and Sinovac 65.6 %. This occurs 9 to 12 weeks after the first shot., Conclusion: The results indicate that the three vaccines protect against symptomatic COVID-19. Nevertheless, they offer different levels of protection. The results also suggest that VE-under a two-shot scheme-reaches its peak 9 to 16 weeks after the first shot. Moreover, there seems to be a trade-off between achieving higher efficiency by administering the 2nd shot earlier or extending the protection period by administering it later., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Background: The global inequity in the distribution of COVID-19 vaccines underscores the urgent need for innovative and cost-effective vaccine technologies to address access disparities and implement local manufacturing capabilities. This is essential for achieving and sustaining widespread immunity, and for ensuring timely protection of vulnerable populations during future booster campaigns in lower- middle income countries (LMICs)., Methods: To address this need, we conducted a phase II clinical trial to evaluate the safety and immunogenicity of the locally manufactured AVX/COVID-12 "Patria" (AVX) vaccine as a booster dose. The vaccine was administered either intramuscularly (IM) or intranasally (IN) to participants who had previously completed a vaccination regimen for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) using adenoviral vector, inactivated virus, or mRNA-based vaccines. Participants with initial anti-spike IgG titers below 1,200 U/mL were included, allowing us to observe the booster effect induced by vaccination., Results: Both IM and IN immunization with AVX were found to be safe and well-tolerated. The vaccine induced a significant (>2.5-fold) increase in neutralizing antibodies against the ancestral Wuhan strain and variants of concern (VOCs), including Alpha, Beta, Delta, and Omicron (BA.2 and BA.5). This immune response was further supported by increased cellular production of interferon-gamma (IFN-γ), demonstrating a robust and multifaceted immune reaction., Conclusions: The administration of AVX as a booster dose, whether through IM or IN routes, was safe and well-tolerated. The vaccine extended immune responses not only against the ancestral Wuhan-1 strain but also against various VOCs. Its ability to enhance preexisting immune responses suggests a potential contribution to expanding and sustaining herd immunity within the population., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Laboratorios Avimex S.A. de C.V. reports financial support was provided by Consejo Nacional de Humanidades, Ciencia y Tecnología. México. Bernardo Lozano-Dubernard reports financial support was provided by Laboratorios Avimex S.A. de C.V. P.P., F.K., and A.G.-S. has patent #62/994,252 pending to Mount Sinai. P.P., F.K., and A.G.-S. has patent #63/018,457 pending to Mount Sinai. P.P., F.K., and A.G.-S. has patent #63/020,503 pending to Mount Sinai. P.P., F.K., and A.G.-S. has patent #63/024,436 pending to Mount Sinai. P.P., F.K., and A.G.-S. has patent #63/251,020 pending to Mount Sinai. M.T., D.S.-M., C.L.-M., H.E.C.-C., F.C.-P., G.P.D.L., and B.L.-D. has patent #PCT/IB2022/058886. MX/a/2021/011439 pending to Avimex S.A. de C.V. The vaccine candidate administered in this study was developed by faculty members at the Icahn School of Medicine at Mount Sinai including P.P., F.K., and A.G.-S. Mount Sinai is seeking to commercialize this vaccine; therefore, the institution and its faculty inventors could benefit financially. The Icahn School of Medicine at Mount Sinai has filed patent applications relating to SARS-849 CoV-2 serological assays (USA Provisional Application Numbers: 62/994,252, 63/018,457, 63/020,503, and 63/024,436) and NDV-based SARS-CoV-2 vaccines (USA Provisional Application Number: 63/251,020) which list F.K. as co-inventor. A.G.-S. and P.P. are co-inventors in the NDV-based SARS-CoV-2 vaccine patent application. Patent applications were submitted by the Icahn School of Medicine at Mount Sinai. Mount Sinai has spun out a company, Kantaro, to market serological tests for SARS-CoV-2 and another company, CastleVax, to commercialize SARS-CoV-2 vaccines. F.K., P.P., and A.G.-S. serve on the scientific advisory board of CastleVax and are listed as co-founders of the company. F.K. has consulted for Merck, Seqirus, Curevac, and Pfizer, and is currently consulting for Gritstone, Third Rock Ventures, GSK, and Avimex. The F.K. laboratory has been collaborating with Pfizer on animal models of SARS-CoV-2. C.L.-M. has consulted for AstraZeneca. The A.G.-S. laboratory has received research support from GSK, Pfizer, Senhwa Biosciences, Kenall Manufacturing, Blade Therapeutics, Avimex, Johnson & Johnson, Dynavax, 7Hills Pharma, Pharmamar, ImmunityBio, Accurius, Nanocomposix, Hexamer, N-fold LLC, Model Medicines, Atea Pharma, Applied Biological Laboratories, and Merck. A.G.-S. has consulting agreements for the following companies involving cash and/or stock: Amovir, Vivaldi Biosciences, Contrafect, 7Hills Pharma, Avimex, Pagoda, Accurius, Esperovax, Farmak, Applied Biological Laboratories, Pharmamar, CureLab Oncology, CureLab Veterinary, Synairgen, Paratus, Pfizer, and Prosetta. A.G.-S. has been an invited speaker in meeting events organized by Seqirus, Janssen, Abbott, and AstraZeneca. PP has a consulting agreement with Avimex. Members of Avimex developed the live vaccine used in this study. Avimex filed patent applications with Mount Sinai and CONAHCYT. M.T., D.S.-M., C.L.-M., H.E.C.-C., F.C.-P., G.P.D.L., and B.L.-D. are named as inventors on at least one of those patent applications. The clinical study was entirely performed in Mexico, and Mount Sinai had no role in it. The rest of the participants are employees of their corresponding institutions and declare no competing interests. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Mexico's pandemic management and the absence of measures have been harshly criticized as being disproportionate. This paper examines whether the proportionality principle was properly applied to Mexico's COVID-19 response and outlines three reasons against such an endeavor, namely (i) the content of "proportionate measures" remained insufficiently well defined, (ii) there were yet fundamental rights conflicts to resolve, and (iii) the situation was moreover characterized by epistemic uncertainty., (© 2023 John Wiley & Sons Ltd.)

Background: Information on Paxlovid™ effectiveness must be monitored and updated in real world scenarios. Our research question was what is the effectiveness of Paxlovid™ in adult patients with COVID-19? Therefore, we investigated the effectiveness of Paxlovid™ on reducing the incidence of pneumonia, hospitalization, and mortality in a cohort of COVID-19 positive adult patients from northeast Mexico., Methods: A retrospective cohort study of COVID-19 positive adult patients from Nuevo Leon, Mexico from December 2020 to May 2023 (after Omicron BA-5 circulation) was performed. Paxlovid™ use was authorized in September 2022. Therefore, we analyzed effectiveness in patients with confirmed diagnosis who met selection criteria between September 2022 and May 2023 (n = 20,799; 5,673 with and 15,126 without Paxlovid™)., Results: The pneumonia (0.1% vs. 0.4%, p < 0.0001), hospitalization (0.1% vs. 1.2%, p < 0.0001), and death rates (0.04% vs. 0.2%, p < 0.0001) were lower in patients with Paxlovid™ treatment independently of age, sex, comorbidity, and COVID-19 and pneumococcal vaccination history. Effectiveness was 88.2%, 95.9% y 91.9% for pneumonia, hospitalization, and death, respectively., Conclusions: Paxlovid™ reduces the presentation of pneumonia, hospitalization, and death secondary to COVID-19. It is recommended to continue monitoring Paxlovid™ effectiveness, as other SARS-CoV-2 variants continue to emerge., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Background: Timely monitoring of SARS-CoV-2 variants is crucial to effectively managing both prevention and treatment efforts. In this paper, we aim to describe demographic and clinical patterns of individuals with COVID-19-like symptoms during the first three epidemic waves in Mexico to identify changes in those patterns that may reflect differences determined by virus variants., Methods: We conducted a descriptive analysis of a large database containing records for all individuals who sought care at the Mexican Social Security Institute (IMSS) due to COVID-19-like symptoms from March 2020 to October 2021 (4.48 million records). We described the clinical and demographic profile of individuals tested (3.38 million, 32% with PCR and 68% with rapid test) by test result (positives and negatives) and untested, and among those tested, and the changes in those profiles across the first three epidemic waves., Results: Individuals with COVID-19-like symptoms were older in the first wave and younger in the third one (the mean age for those positive was 46.6 in the first wave and 36.1 in the third wave; for negatives and not-tested, the mean age was 41 and 38.5 in the first wave and 34.3 and 33.5 in the third wave). As the pandemic progressed, an increasing number of individuals sought care for suspected COVID-19. The positivity rate decreased over time but remained well over the recommended 5%. The pattern of presenting symptoms changed over time, with some of those symptoms decreasing over time (dyspnea 40.6 to 14.0%, cough 80.4 to 76.2%, fever 77.5 to 65.2%, headache 80.3 to 78.5%), and some increasing (odynophagia 48.7 to 58.5%, rhinorrhea 28.6 to 47.5%, anosmia 11.8 to 23.2%, dysgeusia 11.2 to 23.2%)., Conclusion: During epidemic surges, the general consensus was that any individual presenting with respiratory symptoms was a suspected COVID-19 case. However, symptoms and signs are dynamic, with clinical patterns changing not only with the evolution of the virus but also with demographic changes in the affected population. A better understanding of these changing patterns is needed to improve preparedness for future surges and pandemics., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Olaiz, Bertozzi, Juárez-Flores, Borja-Aburto, Vicuña, Ascencio-Montiel and Gutiérrez.)

In this paper we model the spreading of the SARS-CoV-2 in Mexico by introducing a new stochastic approximation constructed from first principles, where the number of new infected individuals caused by a single infectious individual per unit time (a day), is a random variable of a time-dependent Poisson distribution. The model, structured on the basis of a Latent-Infectious-(Recovered or Deceased) (LI(RD)) compartmental approximation together with a modulation of the mean number of new infections (the Poisson parameters), provides a good tool to study theoretical and real scenarios. [ABSTRACT FROM AUTHOR]

Copyright of Dixi is the property of Universidad Cooperativa de Colombia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Dixi is the property of Universidad Cooperativa de Colombia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

As a result of the COVID-19 pandemic, various joint efforts have been made to support the creation of vaccines. Different projects have been under development, of which some are in the clinical evaluation stage and others in are in phase III with positive results. The aim of this paper was to describe the current situation of the development and production of vaccines available to the population to facilitate future research and continue developing and proposing ideas for the benefit of the population. So, we carried out a systematic review using databases such as PubMed, ScienceDirect, SciELO, and MEDLINE, including keywords such as "vaccines," "COVID-19," and "SARS-CoV-2". We reviewed the development and production of the anti-COVID vaccine and its different platforms, the background leading to the massive development of these substances, and the most basic immune aspects for a better understanding of their physiological activity and the immune response in those who receive the vaccine. We also analyzed immunization effects in populations with any medical or physiological conditions (such as immunosuppression, people with comorbidities, and pregnancy), as well as the response to immunization with heterologous vaccines and the hybrid immunity (the combination of natural immunity to SARS-CoV-2 with immunity generated by the vaccine). Likewise, we address the current situation in Mexico and its role in managing the vaccination process against SARS-CoV-2 at the national and international levels. There are still many clinical and molecular aspects to be described, such as the duration of active immunity and the development of immunological memory, to mention some of the most important ones. However, due to the short time since the global vaccination roll-out and that it has been progressive (not counting children and people with medical conditions), it is premature to say whether a second vaccination schedule will be necessary for the near future. Thus, it is essential to continue with health measures. [ABSTRACT FROM AUTHOR]

Humanity has suffered throughout its history from different types of pandemics caused by deadly infectious diseases. Mathematical models are very useful tools to understand the dynamics of the behavior and propagation of these. Among these models are those known as SIS, SIR and SEIR. This paper presents a brief explanation of the structure of these models and its use in some pandemics. In particular, some SIR-type models without and with delays are analyzed with special interest, as well as their applications to the current pandemic caused by the SARS-CoV-2 virus. To determine the correspondence between some of the models analyzed and the data of Infectious and Recovered from Mexico reported by the World Health Organization (WHO), simulations are presented in three different time periods between the years 2020-2021. In addition, an unpublished SIR-type mathematical model with three delays is proposed as a main contribution. Finally, a discussion is given on the application of numerical algorithms to identify some parameters of mathematical models, such as ordinary least squares. [ABSTRACT FROM AUTHOR]

Objective. To determine the relative risk of a lethal outcome associated with chronic degenerative conditions in patients with COVID-19. Methods. A cohort study was conducted using electronic medical records belonging to patients who tested positive for COVID-19 on RT-PCR while receiving care as outpatients or inpatients in a social security system facility between March 2020 and March 2021. Two study groups were formed. The exposed group was divided into four subgroups, each of which was diagnosed with one and only one chronic condition (diabetes, hypertension, obesity, or chronic kidney disease); the unexposed group was obtained from the medical records of patients without comorbidities. A total of 1 114 medical records were examined using simple random sampling. Once the minimum sample size was reached, the relative risk was calculated for each chronic condition. Combinations of two, three, and four conditions were created, and each of them was included in the analysis. Results. In the absence of a chronic degenerative condition, the prevalence of a lethal outcome from COVID-19 is 3.8%; in the presence of type 2 diabetes mellitus, 15.8%; in the presence of arterial hypertension, 15.6%; and in the presence of obesity, 15.0%. For diabetes and hypertension combined, the prevalence of a lethal outcome is 54.1%; for diabetes and obesity combined, 36.8%, and for obesity and hypertension combined, 28.1%. Conclusion. In patients with COVID-19, the relative risk of a lethal outcome is 4.17 for those with diabetes, 4.13 for those with hypertension, and 3.96 for those with obesity. For two chronic conditions combined, the relative risk doubles or triples. The relative risk of a lethal outcome is 14.27 for diabetes plus hypertension; 9.73 for diabetes plus obesity, and 7.43 for obesity plus hypertension. Chronic conditions do not present alone; they generally occur together, hence the significance of the relative risks for lethal outcomes presented in this paper. [ABSTRACT FROM AUTHOR]

COVID-19 is no longer a public health emergency of international concern, but long COVID's effects are yet to be fully understood. Hence, globally, SARS-CoV-2 is still a profound threat to public health and of perilous nature as a zoonotic disease. Timely vaccination provided to individuals worldwide during the pandemic phase was under a certain degree of control; however, few studies have reported the effectiveness of vaccines administered in Mexico, and its surveillance is paramount. Furthermore, an unknown proportion of Mexican individuals have not yet received any vaccine, and the circulation of the Omicron, Pirola, and FLiRT variants is ongoing. A cross-sectional serology survey study design was employed, involving 150 individuals from Southern Mexico (Oaxaca) whose humoral immune responses after vaccination were tested by an ELISA; the receptor-binding domain of the SARS-CoV-2 spike protein served as a recombinant antigen in the ELISA. One hundred thirty-nine out of 150 individuals (92.6%; 95%-CI = 87–95%) examined were positive for the ELISA, but in 11 individuals, the vaccines did not induce any immune response. Interestingly, the immune responses (antibody prevalence and levels) of females (58%) were higher (T= −2.21; p-value = 0.02) than those of males (41%). However, in this sample population of Southern Mexico, age, vaccine type, comorbidity, and body mass index did not have any effect (p > 0.05) after COVID-19 vaccination. Taking all results together, here, we present factors that affected immune responses of individuals during the first vaccination campaign in Oaxaca, Mexico; however, vaccine surveillance during the post-pandemic phase needs further investigation. [ABSTRACT FROM AUTHOR]

Throughout the early stages of the COVID-19 pandemic in Mexico (August—December 2020), we closely followed a cohort of n = 100 healthcare workers. These workers were initially seronegative for Immunoglobulin G (IgG) antibodies against SARS-CoV-2, the virus that causes COVID-19, and maintained close contact with patients afflicted by the disease. We explored the database of demographic, physiological and laboratory parameters of the cohort recorded at baseline to identify potential risk factors for infection with SARS-CoV-2 at a follow-up evaluation six months later. Given that susceptibility to infection may be a systemic rather than a local property, we hypothesized that a multivariate statistical analysis, such as MANOVA, may be an appropriate statistical approach. Our results indicate that susceptibility to infection with SARS-CoV-2 is modulated by sex. For men, different physiological states appear to exist that predispose to or protect against infection, whereas for women, we did not find evidence for divergent physiological states. Intriguingly, male participants who remained uninfected throughout the six-month observation period, had values for mean arterial pressure and waist-to-hip ratio that exceeded the normative reference range. We hypothesize that certain risk factors that worsen the outcome of COVID-19 disease, such as being overweight or having high blood pressure, may instead offer some protection against infection with SARS-CoV-2. [ABSTRACT FROM AUTHOR]

Background. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the virus that causes coronavirus disease 2019 (COVID-19). It is estimated that more than half of new infections are transmitted by asymptomatic people; therefore, the isolation of symptomatic people is not enough to control the spread of the disease. Methods. A total of 171 unvaccinated young adults (18–35 years) from Sonora, Mexico, who underwent a structured survey to identify prior COVID-19 infections, were included in this study. A qualitative determination of anti-SARS-CoV-2 antibodies in serum was performed by lateral flow immunoassay (Certum IgG/IgM Rapid Test™ cassette kit) and neutralizing antibodies were also determined (GenScript cPass assay). Results. A total of 36 people reported a history of COVID-19 infection, and 135 reported no history of COVID-19. In contrast, 49.6% (67/135) of individuals who had not reported a previous SARS-CoV-2 infection were seropositive to the rapid anti-SARS-CoV-2 antibody test, and 48.1% (65/135) of them had neutralizing antibodies. Conclusions. These results suggest that in young adults, SARS-CoV-2 infections could be asymptomatic in a high percentage of individuals, which could contribute in part to the slow control of the current pandemic due to the large number of asymptomatic cases that are contagious and that could be a silent spread of the virus. [ABSTRACT FROM AUTHOR]

Background: The COVID-19 pandemic has progressed rapidly, with the emergence of new virus variants that pose challenges in treating infected individuals. In Mexico, four epidemic waves have been recorded with varying disease severity. To understand the heterogeneity in clinical presentation over time and the sensitivity and specificity of signs and symptoms in identifying COVID-19 cases, an analysis of the changes in the clinical presentation of the disease was conducted. Aim: To analyze the changes in the clinical presentation of COVID-19 among 3.38 million individuals tested for SARS-CoV-2 at the Mexican Social Security Institute (IMSS) from March 2020 to October 2021 and evaluate the predictivity of signs and symptoms in identifying COVID-19 cases. Methods: A retrospective analysis of clinical presentation patterns of COVID-19 among individuals treated at IMSS was performed, contrasting the signs and symptoms among SARS-CoV-2-positive individuals with those who tested negative for the virus but had respiratory infection symptoms. The sensitivity and specificity of each sign and symptom in identifying SARS-CoV-2 infection were estimated. Results: The set of signs and symptoms reported for COVID-19-suspected patients treated at IMSS were not highly specific for SARS-CoV-2 positivity. The signs and symptoms exhibited variability based on age and epidemic wave. The area under the receiver operating characteristic (ROC) curve was 0.62 when grouping the five main symptoms (headache, dyspnea, fever, arthralgia, and cough). Most of the individual symptoms had ROC values close to 0.5 (16 out of 22 between 0.48 and 0.52), indicating non-specificity. Conclusions: The results highlight the difficulty in making a clinical diagnosis of COVID-19 due to the lack of specificity of signs and symptoms. The variability of clinical presentation over time and among age groups highlights the need for further research to differentiate whether the changes are due to changes in the virus, who is becoming infected, or the population, particularly with respect to prior infection and vaccination status. [ABSTRACT FROM AUTHOR]

Background Out-of-hospital deaths increased during peak coronavirus disease 2019 (COVID-19) pandemic periods. However, aside from COVID-19 severity, which variables are related to being hospitalized have not been properly studied. We examine the association of several variables with dying at home from COVID-19 as opposed to in a hospital. Methods We used COVID-19 open data from Mexico City from March 2020 until February 2021. A causal model was prespecified to identify variables of interest. Adjusted logistic regressions were performed to calculate ORs for associations between variables of interest and dying out of hospital due to COVID-19. Results Among 61 112 people who died due to COVID-19, 8080 died out of hospital. Older age (OR 3.49, age 90 vs 60 y), male sex (OR 1.18) and higher bed occupancy (OR 2.68, 90% vs 50% occupancy) were positively associated with dying outside of hospital. Conclusion Older age could confer different patient wishes or less ability to look for healthcare. Higher bed occupancy may have prevented hospital admission from people who required in-hospital care. [ABSTRACT FROM AUTHOR]

Copyright of Revista de la Facultad de Medicina Humana is the property of Instituto de Investigaciones en Ciencias Biomedicas de la Universidad Ricardo Palma and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

SARS‐CoV‐2 can infect pets under natural conditions, which raises questions about the risk factors related to the susceptibility of these animals to infection. The status of pet infection by SARS‐CoV‐2 in Mexico is not well‐understood. We aimed to estimate the frequency of positive household cats and dogs to viral RNA and antibodies for SARS‐CoV‐2 during the second wave of human infections in Mexico, and to recognize the major risk factors related to host and pet ownership behaviour. We evaluated two study groups, cats and dogs from COVID‐19‐infected/‐suspected households (n = 44) and those admitted for veterinary care for any reason at several veterinary hospitals in Puebla City, Mexico (n = 91). Using RT‐PCR, we identified the presence of SARS‐CoV‐2 RNA in swabs of four dogs (18.18%) and zero cats in COVID‐19‐infected/‐suspected households; within this group, 31.82% of dogs and 27.27% of cats were tested IgG ELISA‐positive; and neutralizing antibodies were detected in one dog (4.55%) and two cats (9.09%). In the random group (pets evaluated at private clinics and veterinary teaching hospital), 25.00% of dogs and 43.59% of cats were ELISA‐positive and only one cat showed neutralizing antibodies (2.56%). Older than 4‐year‐old, other pets at home, and daily cleaning of pet dish, were each associated with an increase in SARS‐CoV‐2 infection (p < 0.05). Allowing face lick, sharing bed/food with pets and owner tested positive or suspected COVID‐19 were not significant risk factors, but more than 4 h the owner spent away from home during the lockdown for COVID‐19 (OR = 0.37, p = 0.01), and outdoor pet food tray (OR = 0.32, p = 0.01) significantly decreased the risks of SARS‐CoV‐2 infection in pets, suggesting that time the owner spends with their pet is an important risk factor. [ABSTRACT FROM AUTHOR]

Background: One of the risk factors for getting seriously ill from COVID-19 and reaching high mortality rates is older age. Older age is also associated with comorbidities, which are risk factors for severe COVID-19 infection. Among the tools that have been evaluated to predict intensive care unit (ICU) admission and mortality is ABC-GOALScl. Aim: In the present study we validated the utility of ABC-GOALScl to predict in-hospital mortality in subjects over 60 years of age who were positive for SARS-CoV-2 virus at the moment of admission with the purpose of optimizing sanitary resources and offering personalized treatment for these patients. Methods: This was an observational, descriptive, transversal, non-interventional and retrospective study of subjects (≥ 60 years of age), hospitalized due to COVID-19 infection at a general hospital in northeastern Mexico. A logistical regression model was used for data analysis. Results: Two hundred forty-three subjects were included in the study, whom 145 (59.7%) passed away, while 98 (40.3%) were discharged. Average age was 71, and 57.6% were male. The prediction model ABC-GOALScl included sex, body mass index, Charlson comorbidity index, dyspnea, arterial pressure, respiratory frequency, SpFi coefficient (Saturation of oxygen/Fraction of inspired oxygen ratio), serum levels of glucose, albumin, and lactate dehydrogenase; all were measured at the moment of admission. The area under the curve for the scale with respect to the variable of discharge due to death was 0.73 (IC 95% = 0.662—0.792). Conclusion: The ABC-GOALScl scale to predict ICU admission in COVID-19 patients is also useful to predict in-hospital death in COVID-19 patients ≥ 60 years old. [ABSTRACT FROM AUTHOR]

We aimed to estimate the lead time and infection prevalence from SARS-CoV-2 wastewater (WW) monitoring compared with clinical surveillance data in Mexico to generate evidence about the feasibility of a large-scale WW surveillance system. We selected 10 WW treatment plants (WWTP) and 5 COVID-19 hospitals in major urban conglomerates in Mexico and collected biweekly 24-h flow-adjusted composite samples during October–November 2020. We concentrated WW samples by polyethylene glycol precipitation and employed quantitative PCR (RT-qPCR) assays, targeting the nucleoprotein (N1 and N2) genes. We detected and quantified SARS-CoV-2 RNA in 88% and 58% of the raw WW samples from WWTPs and COVID-19 hospitals, respectively. The WW RNA daily loads lead the active cases by more than one month in large and medium WWTP sites. WW estimated that cases were 2 to 20-fold higher than registered active cases. Developing a continuous monitoring surveillance system for SARS-CoV-2 community transmission through WW is feasible, informative, and recognizes three main challenges: (1) WW system data (catchment area, population served), (2) capacity to maintain the cold-chain and process samples, and (3) supplies and personnel to ensure standardized procedures. [ABSTRACT FROM AUTHOR]

Copyright of Salud Pública de México is the property of Instituto Nacional de Salud Publica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The COVID-19 pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has been one of the most catastrophic diseases observed in recent years. It has reported nearly 550 million cases worldwide, with more than 6.35 million deaths. In Mexico, an increased incidence and mortality of this disease were observed, where the immune response has been involved in the magnitude and severity. A critical version of the disease is accompanied by hyperinflammatory responses, with cytokine and defective cellular responses. A detailed understanding of the role of molecules and cells in the immune response during COVID-19 disease may help to generate effective protection mechanisms, improving those we already have. Here we analyzed blood samples obtained from patients at the Hospital Regional de Alta Especialidad de Ixtapaluca (HRAEI), Mexico, which were classified according to living guidance for clinical management of COVID-19 by the World Health Organization: asymptomatic, mild, severe, and critical disease. We observed increased interleukin (IL)-6 levels and a T-CD8+ and T-CD4+ cell reduction correlated with the critical disease version. Importantly, here, we described a significant reduction of CD11b+CD45highCD14low monocytes during severe disease, which displayed a non-classical profile, expressing IL-10, transforming growth factor (TGF)-β, and indoleamine 2,3-dioxygenase (IDO)1 molecule. Moreover, CD11b+CD45highCD14low monocytes obtained from infected one-dose vaccinated patients (Pfizer® vaccine) who suffered minimal symptoms showed simultaneously a dual classical and no-classical profile expressing pro- and anti-inflammatory cytokines. These results suggest that blood monocytes expressing a dual pro- and anti-inflammatory profile might be a predictive marker for protection in the Mexican population during COVID-19 disease. Key points : • Exacerbated immune response is associated with COVID-19 severe disease. • Dual monocyte activation profile is crucial for predicting protection during COVID-19. • Vaccination is crucial to induce the dual activation profile in monocytes. [ABSTRACT FROM AUTHOR]

A new variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), named Omicron (Pango lineage designation B.1.1.529), was first reported to the World Health Organization by South African health authorities on 24 November 2021. The Omicron variant possesses numerous mutations associated with increased transmissibility and immune escape properties. In November 2021, Mexican authorities reported Omicron's presence in the country. In this study, we infer the first introductory events of Omicron and the impact that human mobility has had on the spread of the virus. We also evaluated the adaptive evolutionary processes in Mexican SARS-CoV-2 genomes during the first month of the circulation of Omicron. We inferred 160 introduction events of Omicron in Mexico since its first detection in South Africa; subsequently, after the first introductions there was an evident increase in the prevalence of SARS-CoV-2 during January. This higher prevalence of the novel variant resulted in a peak of reported cases; on average 6 weeks after, a higher mobility trend was reported. During the peak of cases in the country from January to February 2022, the Omicron BA.1.1 sub-lineage dominated, followed by the BA.1 and BA.15 sub-lineages. Additionally, we identified the presence of diversifying natural selection in the genomes of Omicron and found six non-synonymous mutations in the receptor binding domain of the spike protein, all of them related to evasion of the immune response. In contrast, the other proteins in the genome are highly conserved; however, we identified homoplasic mutations in non-structural proteins, indicating a parallel evolution. [ABSTRACT FROM AUTHOR]

The coordinated efforts to stop the spread of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) include massive immunization of the population at a global scale. The humoral immunity against COVID-19 is conferred by neutralizing antibodies (NAbs) that occur during the post-infection period and upon vaccination. Here, we provide robust data showing that potent neutralizing antibodies are induced in convalescent patients of SARS-CoV-2 infection who have been immunized with different types of vaccines, and patients with no previous history of COVID-19 immunized with a mixed vaccination schedule regardless of the previous infection. More importantly, we showed that a heterologous prime-boost in individuals with Ad5-nCoV (Cansino) vaccine induces higher NAbs levels in comparison to a single vaccination scheme alone. [ABSTRACT FROM AUTHOR]

Background and Objectives: An association between high red blood cell distribution width (RDW) and mortality has been found in several diseases, including infection and sepsis. Some studies have aimed at determining the association of elevated RDW with adverse prognosis in COVID-19, but its usefulness has not been well established. The objective of this study was to determine the accuracy of the RDW, measured at hospital admission and discharge, for predicting death in patients with COVID-19. Materials andMethods: An observational, retrospective, longitudinal, and analytical study was conducted in two different COVID-19 reference centers in the state of Guanajuato, Mexico. A total of 323 patients hospitalized by COVID-19 were included. Results: We found higher RDW levels at the time of hospital admission in the non-survivors group compared to levels in survivors (median = 13.6 vs. 13.0, p < 0.001). Final RDW levels were even higher in the deceased group when compared with those of survivors (median = 14.6 [IQR, 12.67–15.6] vs. 12.9 [IQR, 12.2–13.5], p < 0.001). For patients who died, an RDW > 14.5% was more common at the time of death than for patients who survived at the time of discharge (81 vs. 13 patients, p < 0.001; RR = 2.3, 95% CI 1.89–2.81). Conclusions: The RDW is an accessible and economical parameter that, together with other characteristics of the presentation and evolution of patients with COVID-19, can be helpful in determining the prognosis. An RDW that increases during hospitalization could be a more important mortality predictor than the RDW at hospital admission. [ABSTRACT FROM AUTHOR]

Serosurveillance helps establish reopening guidelines and determine the immunity levels in different populations to reach herd immunity. Then, there is an urgent need to estimate seroprevalence population wide. In Mexico, information about COVID-19 cases and related deaths is scarce. Also, there is no official serosurveillance, limiting our knowledge of the impact of the SARS-CoV-2 pandemic. Here, we report the prevalence of anti-SARS-CoV-2 antibodies in 522,690 unvaccinated people from July 5th to December 31st, 2020. The overall seroprevalence was 32.8% and highest in adults aged 30–39 years (38.5%) than people under 20 years (33.0%) or older (28.9%). Moreover, in a cohort of 1655 individuals confirmed COVID-19 by PCR, we found that symptomatic people (HR = 2.56) increased seroconversion than presymptomatic. Also, we identified that the most discriminative symptoms for COVID-19 that could predict seroconversion were anosmia and ageusia (HR = 1.70), fever, myalgia/arthralgia, and cough (HR = 1.75). Finally, we found that obese people had lower seroconversion (HR = 0.53) than healthy people, but the opposite happens in diabetic people (HR = 1.39). These findings reveal that around one-third of Mexican outpatients had anti-SARS-CoV-2 antibodies before vaccination. Also, some symptoms improve empirically COVID-19 diagnosis and seroconversion. This information could help fine-tune vaccination schemes and the reopening and back-to-work algorithms. [ABSTRACT FROM AUTHOR]

Seroprevalence surveys provide estimates of the extent of SARS-CoV-2 infections in the population, regardless of disease severity and test availability. In Mexico in 2020, COVID-19 cases reached a maximum in July and December. We aimed to estimate the national and regional seroprevalence of SARS-CoV-2 antibodies across demographic and socioeconomic groups in Mexico after the first wave, from August to November 2020. We used nationally representative survey data including 9,640 blood samples. Seroprevalence was estimated by socioeconomic and demographic characteristics, adjusting by the sensitivity and specificity of the immunoassay test. The national seroprevalence of SARS-CoV-2 antibodies was 24.9% (95%CI 22.2, 26.7), being lower for adults 60 years and older. We found higher seroprevalence among urban and metropolitan areas, low socioeconomic status, low education and workers. Among seropositive people, 67.3% were asymptomatic. Social distancing, lockdown measures and vaccination programs need to consider that vulnerable groups are more exposed to the virus and unable to comply with lockdown measures. SARS-CoV-2 seroprevalence surveys provide estimates of the extent of prior infection in a population. In this nationally representative survey from Mexico, the authors estimate seroprevalence after the first epidemic wave at ~25%, with variation by region, age, socioeconomic status, and education level. [ABSTRACT FROM AUTHOR]