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Background Respiratory syncytial virus (RSV) is a major cause of hospitalizations in young children. We estimated the burden of community-onset RSV-associated hospitalizations among US children aged <2 years by extrapolating rates of RSV-confirmed hospitalizations in 4 surveillance states and using probabilistic multipliers to adjust for ascertainment biases. Methods From October 2014 through April 2015, clinician-ordered RSV tests identified laboratory-confirmed RSV hospitalizations among children aged <2 years at 4 influenza hospitalization surveillance network sites. Surveillance populations were used to estimate age-specific rates of RSV-associated hospitalization, after adjusting for detection probabilities. We extrapolated these rates using US census data. Results We identified 1554 RSV-associated hospitalizations in children aged <2 years. Of these, 27% were admitted to an intensive care unit, 6% needed mechanical ventilation, and 5 died. Most cases (1047/1554; 67%) had no underlying condition. Adjusted age-specific RSV hospitalization rates per 100 000 population were 1970 (95% confidence interval [CI],1787 to 2177), 897 (95% CI, 761 to 1073), 531 (95% CI, 459 to 624), and 358 (95% CI, 317 to 405) for ages 0–2, 3–5, 6–11, and 12–23 months, respectively. Extrapolating to the US population, an estimated 49 509–59 867 community-onset RSV-associated hospitalizations among children aged <2 years occurred during the 2014–2015 season. Conclusions Our findings highlight the importance of RSV as a cause of hospitalization, especially among children aged <2 months. Our approach to estimating RSV-related hospitalizations could be used to provide a US baseline for assessing the impact of future interventions. [ABSTRACT FROM AUTHOR]

Background Nicaragua implemented an influenza vaccination program for pregnant women with high-risk obstetric conditions in 2007. In 2014, the recommendation of influenza vaccination expanded to include all pregnant women. Given the expansion in the recommendation of vaccination, we evaluated knowledge, attitudes and practices of pregnant women and their healthcare providers towards influenza vaccination and its recommendation. Methods We conducted surveys among pregnant women and their healthcare providers from June to August 2016 at two hospitals and 140 health facilities in Managua. The questions were adapted from the U.S. national CDC influenza survey and related to knowledge, attitudes and practices about influenza vaccination and barriers to vaccination. We analyzed reasons for not receiving vaccination among pregnant women as well as receipt of vaccination recommendation and offer by their healthcare providers. Results Of 1,303 pregnant women enrolled, 42% (5 4 5) reported receiving influenza vaccination in the 2016 season. Of those who reported not receiving vaccination, 46% indicated barriers to vaccination. Pregnant women who were vaccinated were more likely to be aware of the recommendation for vaccination and the risks of influenza illness during pregnancy and to perceive the vaccine as safe and effective, compared to unvaccinated pregnant women (p-values < 0.001). Of the 619 health workers enrolled, over 89% recalled recommending influenza vaccination to all pregnant women, regardless of obstetric risk. Of the 1,223 women who had a prenatal visit between the start date of the influenza vaccination and the time of interview, 44% recalled receiving a recommendation for influenza vaccination and 43% were offered vaccination. Vaccination rates were higher for those receiving a recommendation and offer of vaccination compared with those who received neither (95% vs 5%, p-value < 0.001). Conclusion Pregnant women in Managua had positive perceptions of influenza vaccine and were receptive to receiving influenza vaccination, especially after the offer and recommendation by their healthcare providers. [ABSTRACT FROM AUTHOR]

Background: Studies have shown that influenza vaccination during pregnancy reduces the risk of influenza disease in pregnant women and their offspring. Some have proposed that maternal vaccination may also have beneficial effects on birth outcomes. In 2014, we conducted an observational study to test this hypothesis using data from two large hospitals in Managua, Nicaragua. Methods: We conducted a retrospective cohort study to evaluate associations between influenza vaccination and birth outcomes. We carried out interviews and reviewed medical records post-partum to collect data on demographics, influenza vaccination during pregnancy, birth outcomes and other risk factors associated with adverse neonatal outcomes. We used influenza surveillance data to adjust for timing of influenza circulation. We assessed self-reports of influenza vaccination status by further reviewing medical records of those who self-reported but did not have readily available evidence of vaccination status. We performed multiple logistic regression (MLR) and propensity score matching (PSM). Results: A total of 3268 women were included in the final analysis. Of these, 55% had received influenza vaccination in 2014. Overall, we did not observe statistically significant associations between influenza vaccination and birth outcomes after adjusting for risk factors, with either MLR or PSM. With PSM, after adjusting for risk factors, we observed protective associations between influenza vaccination in the second and third trimester and preterm birth (aOR: 0.87; 95% confidence interval (CI): 0.75–0.99 and aOR: 0.66; 95% CI: 0.45–0.96, respectively) and between influenza vaccination in the second trimester and low birth weight (aOR: 0.80; 95% CI: 0.64–0.97). Conclusions: We found evidence to support an association between influenza vaccination and birth outcomes by trimester of receipt with data from an urban population in Nicaragua. The study had significant selection and recall biases. Prospective studies are needed to minimize these biases. [ABSTRACT FROM AUTHOR]

Background. From January 2014-July 2014, more than 46 000 unaccompanied children (UC) from Central America crossed the US-Mexico border. In June-July, UC aged 9-17 years in 4 shelters and 1 processing center in 4 states were hospitalized with acute respiratory illness. We conducted a multistate investigation to interrupt disease transmission. Methods. Medical charts were abstracted for hospitalized UC. Nonhospitalized UC with influenza-like illness were interviewed, and nasopharyngeal and oropharyngeal swabs were collected to detect respiratory pathogens. Nasopharyngeal swabs were used to assess pneumococcal colonization in symptomatic and asymptomatic UC. Pneumococcal blood isolates from hospitalized UC and nasopharyngeal isolates were characterized by serotyping and whole-genome sequencing. Results. Among 15 hospitalized UC, 4 (44%) of 9 tested positive for influenza viruses, and 6 (43%) of 14 with blood cultures grew pneumococcus, all serotype 5. Among 48 nonhospitalized children with influenza-like illness, 1 or more respiratory pathogens were identified in 46 (96%). Among 774 nonhospitalized UC, 185 (24%) yielded pneumococcus, and 70 (38%) were serotype 5. UC transferring through the processing center were more likely to be colonized with serotype 5 (odds ratio, 3.8; 95% confidence interval, 2.1- 6.9). Analysis of core pneumococcal genomes detected 2 related, yet independent, clusters. No pneumococcus cases were reported after pneumococcal and influenza immunization campaigns. Conclusions. This respiratory disease outbreak was due to multiple pathogens, including Streptococcus pneumoniae serotype 5 and influenza viruses. Pneumococcal and influenza vaccinations prevented further transmission. Future efforts to prevent similar outbreaks will benefit from use of both vaccines. [ABSTRACT FROM AUTHOR]

Background Pregnant women are at risk of severe influenza disease and are a priority group for influenza vaccination programs. Nicaragua expanded recommendations to include influenza vaccination to all pregnant women in the municipality of Managua in 2013. Methods We carried out a survey among 1,807 pregnant women who delivered at public hospitals in the municipality of Managua to evaluate the uptake of influenza vaccination and factors associated with vaccination. Results We observed a high (71%) uptake of influenza vaccination among this population, with no differences observed by age, education or parity of the women. Having four antenatal visits and five or more visits were associated with receipt of influenza vaccination (AORs: 2.58; 95% CI: 1.15, 5.81, and 2.37; 95% CI: 1.12, 5.0, respectively). Also, receipt of influenza vaccination recommendation from a health care provider was positively associated with receipt of influenza vaccination (AOR: 14.22; 95% CI: 10.45, 19.33). Conclusions The successful expansion of influenza vaccination among pregnant women in the municipality of Managua may be due to ready access to free medical care and health care providers’ recommendation for vaccination at health care clinics that received influenza vaccine. [ABSTRACT FROM AUTHOR]

Newly emerged highly pathogenic avian influenza (HPAI) A H5 viruses have caused outbreaks among birds in the United States. These viruses differ genetically from HPAI H5 viruses that previously caused human illness, most notably in Asia and Africa. To assess the risk for animal-to-human HPAI H5 virus transmission in the United States, we determined the number of persons with self-reported exposure to infected birds, the number with an acute respiratory infection (ARI) during a 10-day postexposure period, and the number with ARI who tested positive for influenza by real-time reverse transcription PCR or serologic testing for each outbreak during December 15, 2014-March 31, 2015. During 60 outbreaks in 13 states, a total of 164 persons were exposed to infected birds. ARI developed in 5 of these persons within 10 days of exposure. H5 influenza virus infection was not identified in any persons with ARI, suggesting a low risk for animal-to-human HPAI H5 virus transmission. [ABSTRACT FROM AUTHOR]

Background: Some studies suggest that influenza vaccination might be protective against severe influenza outcomes in vaccinated persons who become infected. We used data from a large surveillance network to further investigate the effect of influenza vaccination on influenza severity in adults aged ≥50 years who were hospitalized with laboratory-confirmed influenza.Methods: We analyzed influenza vaccination and influenza severity using Influenza Hospitalization Surveillance Network (FluSurv-NET) data for the 2012-2013 influenza season. Intensive care unit (ICU) admission, death, diagnosis of pneumonia, and hospital and ICU lengths of stay served as measures of disease severity. Data were analyzed by multivariable logistic regression, parametric survival models, and propensity score matching (PSM).Results: Overall, no differences in severity were observed in the multivariable logistic regression model. Using PSM, adults aged 50-64 years (but not other age groups) who were vaccinated against influenza had a shorter length of ICU stay than those who were unvaccinated (hazard ratio for discharge, 1.84; 95% confidence interval, 1.12-3.01).Conclusions: Our findings show a modest effect of influenza vaccination on disease severity. Analysis of data from seasons with different predominant strains and higher estimates of vaccine effectiveness are needed. [ABSTRACT FROM AUTHOR]

Background Influenza vaccination is recommended annually for all persons 6 months and older. Reports of increased influenza-related morbidity and mortality during the 2013–2014 influenza season raised concerns about low adult influenza immunization rates in Puerto Rico. In order to inform public health actions to increase vaccination rates, we surveyed adults in Puerto Rico regarding influenza vaccination-related attitudes and barriers. Methods A random-digit-dialing telephone survey (50% landline: 50% cellphone) regarding influenza vaccination, attitudes, practices and barriers was conducted November 19–25, 2013 among adults in Puerto Rico. Survey results were weighted to reflect sampling design and adjustments for non-response. Results Among 439 surveyed, 229 completed the survey with a 52% response rate. Respondents’ median age was 55 years; 18% reported receiving 2013–2014 influenza vaccination. Among 180 unvaccinated respondents, 38% reported barriers associated with limited access to vaccination, 24% reported they did not want or need influenza vaccination, and 20% reported safety concerns. Vaccinated respondents were more likely to know if they were recommended for influenza vaccination, to report greater perceived risk of influenza illness, and to report being less concerned about influenza vaccine safety ( p -value < 0.05). Of the 175 respondents who saw a healthcare provider (HCP) since July 1, 2013, 38% reported their HCP recommended influenza vaccination and 17% were offered vaccination. Vaccination rates were higher among adults who received a recommendation and/or offer of influenza vaccination (43% vs. 14%; p -value < 0.01). Conclusions Failure of HCP to recommend and/or offer influenza vaccination and patient attitudes (low perceived risk of influenza virus infection) may have contributed to low vaccination rates during the 2013–2014 season. HCP and public health practitioners should strongly recommend influenza vaccination and provide vaccinations during clinical encounters or refer patients for vaccination. [ABSTRACT FROM AUTHOR]

Taenia solium infection causes severe neurological disease in humans. Even though infection and exposure to swine cysticercosis is scattered throughout endemic villages, location of the tapeworm only explains some of the nearby infections and is not related to location of seropositive pigs. Other players might be involved in cysticercosis transmission. In this study we hypothesize that pigs that carry nematodes specific to dung beetles are associated with cysticercosis infection and/or exposure. We carried out a cross-sectional study of six villages in an endemic region in northern Peru. We euthanized all pigs (326) in the villages and performed necropsies to diagnose cysticercosis. For each pig, we counted cysticerci; measured anti-cysticercus antibodies; identified intestinal nematodes; tabulated distance to nearest human tapeworm infection; and recorded age, sex, productive stage, and geographic reference. For the purpose of this paper, we defined cysticercosis infection as the presence of at least one cysticercus in pig muscles, and cysticercosis exposure as seropositivity to anti-cysticercus antibodies with the presence of 0–5 cysticerci. Compared to pigs without nematode infections, those pigs infected with the nematode Ascarops strongylina were significantly associated with the presence of cysticerci (OR: 4.30, 95%CI: 1.83–10.09). Similarly, pigs infected with the nematode Physocephalus sexalatus were more likely to have cysticercosis exposure (OR: 2.21, 95%CI: 1.50–3.28). In conclusion, our results suggest that there appears to be a strong positive association between the presence of nematodes and both cysticercosis infection and exposure in pigs. The role of dung beetles in cysticercosis dynamics should be further investigated. Author Summary: In endemic areas, pigs acquire cysticercosis when ingesting Taenia solium eggs that have been released into the environment in the feces of a person infected with T. solium. The present study has found evidence that players, such as dung beetles, might be involved in further dissemination of the parasite into the environment. Specifically, we found an association between helminths, for whom dung beetles act as an intermediate host, and porcine cysticercosis infection and exposure after adjusting for other porcine cysticercosis predictors such as distance to tapeworm carrier and age. Although the study does not evaluate dung beetles directly, parasites specific to dung beetles serve as a novel proxy to evidence the potential role of dung beetles in the epidemiology of cysticercosis. Therefore, it is important that further studies elucidate the role of other players in cysticercosis transmission in order to better explain the reemergence and persistence of cysticercosis after elimination and control efforts. In addition, vector populations could potentially be used as markers for cysticercosis in the communities. [ABSTRACT FROM AUTHOR]

Taenia solium infection causes severe neurological disease in humans. Even though infection and exposure to swine cysticercosis is scattered throughout endemic villages, location of the tapeworm only explains some of the nearby infections and is not related to location of seropositive pigs. Other players might be involved in cysticercosis transmission. In this study we hypothesize that pigs that carry nematodes specific to dung beetles are associated with cysticercosis infection and/or exposure. We carried out a cross-sectional study of six villages in an endemic region in northern Peru. We euthanized all pigs (326) in the villages and performed necropsies to diagnose cysticercosis. For each pig, we counted cysticerci; measured anti-cysticercus antibodies; identified intestinal nematodes; tabulated distance to nearest human tapeworm infection; and recorded age, sex, productive stage, and geographic reference. For the purpose of this paper, we defined cysticercosis infection as the presence of at least one cysticercus in pig muscles, and cysticercosis exposure as seropositivity to anti-cysticercus antibodies with the presence of 0–5 cysticerci. Compared to pigs without nematode infections, those pigs infected with the nematode Ascarops strongylina were significantly associated with the presence of cysticerci (OR: 4.30, 95%CI: 1.83–10.09). Similarly, pigs infected with the nematode Physocephalus sexalatus were more likely to have cysticercosis exposure (OR: 2.21, 95%CI: 1.50–3.28). In conclusion, our results suggest that there appears to be a strong positive association between the presence of nematodes and both cysticercosis infection and exposure in pigs. The role of dung beetles in cysticercosis dynamics should be further investigated. [ABSTRACT FROM AUTHOR]

This article presents information on influenza activity in the U.S. from September 29, 2013 through February 8, 2014. The types of influenza viruses that were detected during this period include influenza A(H1N1) and pdm09(H1N1) viruses, as well as influenza B and A (H3N2) viruses. It discusses the viral surveillance collaboration in the U.S., antigenic characterization and antiviral resistance of influenza viruses.

We report the first detection of methicillin-resistant Staphylococcus aureus isolates in pigs in Peru. The isolates belong to a livestock-associated lineage previously reported in North America and Europe, CC398, and a highly virulent USA300-like ST8-IV variant, which is the predominant community-associated lineage in Latin America. [ABSTRACT FROM AUTHOR]

Background Diabetes mellitus (DM) is common among older adults hospitalized with influenza, yet data are limited on the impact of DM on risk of severe influenza-associated outcomes. Methods We included adults aged ≥65 years hospitalized with influenza during 2012–2013 through 2016–2017 from the Influenza Hospitalization Surveillance Network (FluSurv-NET), a population-based surveillance system for laboratory-confirmed influenza-associated hospitalizations conducted in defined counties within 13 states. We calculated population denominators using the Centers for Medicare and Medicaid Services county-specific DM prevalence estimates and National Center for Health Statistics population data. We present pooled rates and rate ratios (RRs) of intensive care unit (ICU) admission, pneumonia diagnosis, mechanical ventilation, and in-hospital death for persons with and without DM. We estimated RRs and 95% confidence intervals (CIs) using meta-analysis with site as a random effect in order to control for site differences in the estimates. Results Of 31 934 hospitalized adults included in the analysis, 34% had DM. Compared to those without DM, adults with DM had higher rates of influenza-associated hospitalization (RR, 1.57 [95% CI, 1.43–1.72]), ICU admission (RR, 1.84 [95% CI, 1.67–2.04]), pneumonia (RR, 1.57 [95% CI, 1.42–1.73]), mechanical ventilation (RR, 1.95 [95% CI, 1.74–2.20]), and in-hospital death (RR, 1.48 [95% CI, 1.23–1.80]). Conclusions Older adults with DM have higher rates of severe influenza-associated outcomes compared to those without DM. These findings reinforce the importance of preventing influenza virus infections through annual vaccination, and early treatment of influenza illness with antivirals in older adults with DM. [ABSTRACT FROM AUTHOR]

Background Few studies have examined influenza vaccine effectiveness (VE) among women during pregnancy in middle-income countries. We used data from a prospective cohort of women who were pregnant in Peru to estimate effectiveness of the 2018 Southern Hemisphere influenza vaccine. Methods Women at <28 weeks gestation were enrolled from 4 tertiary level hospitals in Lima, Peru at the start of the 2018 influenza season and followed until the end of their pregnancies. Participants had mid-turbinate nasal swabs collected and tested for influenza by reverse-transcription polymerase chain reaction (RT-PCR) with onset of ≥1 of myalgia, cough, runny nose or nasal congestion, sore throat, or difficulty breathing. Time-varying Cox proportional hazard regression models were used to estimate the risk of RT-PCR-confirmed influenza infection after adjusting for inverse probability treatment weight. Results We followed 1896 women for a median of 127 days (interquartile range [IQR], 86–174). Participants had a median age of 29 years (IQR, 24–34). Among the 1896 women, 49% were vaccinated with the 2018 influenza vaccine and 1039 (55%) developed influenza-like illness, 76 (7%) of whom had RT-PCR-confirmed influenza. Incidence rates of RT-PCR-confirmed influenza were 36.6 and 15.3 per 100 000 person-days among women who were unvaccinated and vaccinated, respectively. Adjusted influenza VE was 22% (95% confidence interval, −64.1% to 62.9%). Conclusions Participants vaccinated against influenza had more than 50% lower incidence of RT-PCR-confirmed influenza illness. Although the VE estimated through propensity weight-adjusted time-varying Cox regression did not reach statistical significance, our findings provide additional evidence about the value of maternal influenza vaccination in middle-income countries. [ABSTRACT FROM AUTHOR]

Background: Influenza vaccination during pregnancy prevents influenza among women and their infants but remains underused among pregnant women. We aimed to quantify the risk of antenatal influenza and examine its association with perinatal outcomes.Methods: We did a prospective cohort study in pregnant women in India, Peru, and Thailand. Before the 2017 and 2018 influenza seasons, we enrolled pregnant women aged 18 years or older with expected delivery dates 8 weeks or more after the season started. We contacted women twice weekly until the end of pregnancy to identify illnesses with symptoms of myalgia, cough, runny nose or nasal congestion, sore throat, or difficulty breathing and collected mid-turbinate nasal swabs from symptomatic women for influenza real-time RT-PCR testing. We assessed the association of antenatal influenza with preterm birth, late pregnancy loss (≥13 weeks gestation), small for gestational age (SGA), and birthweight of term singleton infants using Cox proportional hazards models or generalised linear models to adjust for potential confounders.Findings: Between March 13, 2017, and Aug 3, 2018, we enrolled 11 277 women with a median age of 26 years (IQR 23-31) and gestational age of 19 weeks (14-24). 1474 (13%) received influenza vaccines. 310 participants (3%) had influenza (270 [87%] influenza A and 40 [13%] influenza B). Influenza incidences weighted by the population of women of childbearing age in each study country were 88·7 per 10 000 pregnant woman-months (95% CI 68·6 to 114·8) during the 2017 season and 69·6 per 10 000 pregnant woman-months (53·8 to 90·2) during the 2018 season. Antenatal influenza was not associated with preterm birth (adjusted hazard ratio [aHR] 1·4, 95% CI 0·9 to 2·0; p=0·096) or having an SGA infant (adjusted relative risk 1·0, 95% CI 0·8 to 1·3, p=0·97), but was associated with late pregnancy loss (aHR 10·7, 95% CI 4·3 to 27·0; p<0·0001) and reduction in mean birthweight of term, singleton infants (-55·3 g, 95% CI -109·3 to -1·4; p=0·0445).Interpretation: Women had a 0·7-0·9% risk of influenza per month of pregnancy during the influenza season, and antenatal influenza was associated with increased risk for some adverse pregnancy outcomes. These findings support the added value of antenatal influenza vaccination to improve perinatal outcomes.Funding: US Centers for Disease Control and Prevention.Translations: For the Thai, Hindi, Marathi and Spanish translations of the abstract see Supplementary Materials section. [ABSTRACT FROM AUTHOR]

Background Influenza vaccination may reduce illness severity among those with influenza; however, data are limited. We determined whether outcomes were less severe among vaccinated compared with unvaccinated adults hospitalized with influenza over 5 seasons. Methods We included adults (≥18 years) hospitalized with laboratory-confirmed influenza during seasons 2013–2014 through 2017–2018 and identified through the US Influenza Hospitalization Surveillance Network (FluSurv-NET). Vaccination status was obtained through medical records, vaccine registries, and interviews. We excluded patients who were institutionalized, did not receive antivirals, or had unknown vaccine status or vaccine receipt <14 days before positive influenza test. We used inverse propensity score weighting to balance differences between vaccinated and unvaccinated groups and multivariable logistic and competing risk regression to evaluate the association between vaccination and outcomes including pneumonia, intensive care unit (ICU) admission, mechanical ventilation (MV), death, and ICU and hospital length of stay (LOS) in days. Models were adjusted for season and admission timing in relation to timing of antiviral treatment, symptom onset and season peak. Results Among 67,452 adults hospitalized with influenza, 43,608 were included; 47% were 18–64 years (38% vaccinated) and 53% were ≥65 years (65% vaccinated). Among patients with influenza A(H1N1)pdm09, vaccination was associated with decreased odds of ICU admission (odds ratio (OR) 0.81; OR 0.72) and MV (OR 0.66; OR 0.54) in adults 18–64 and ≥65 years, respectively; decreased odds of pneumonia (OR 0.83), death (OR 0.64) and shortened ICU LOS (relative hazard (RH) 0.82) in adults 18–64 years; and shortened hospital LOS (RH 0.91) in adults ≥65 years (figure). Vaccination was not associated with attenuation of severe outcomes in patients with influenza A(H3N2) and B. Conclusion Vaccination was associated with reduced odds of severe outcomes, including death, by up to 36% in adults hospitalized with influenza A(H1N1)pdm09. All adults without contraindications should receive annual influenza vaccination as there is evidence that it can improve outcomes among those who develop influenza despite vaccination. Disclosures All Authors: No reported Disclosures. [ABSTRACT FROM AUTHOR]

Background: Within‐country differences in the timing of RSV and influenza epidemics have not been assessed in Argentina, the eighth largest country in the world by area. Objective: We aimed to compare seasonality for RSV and influenza both nationally and in each of the five regions to inform Argentina's prevention and treatment guidelines. Method: The Argentine National Laboratories and Health Institutes Administration collected respiratory specimens from clinical practices, outbreak investigations, and respiratory virus surveillance in 2007‐2016; these were tested using immunofluorescence or RT‐PCR techniques. We calculated weekly percent positive (PP) and defined season onset as >2 consecutive weeks when PP exceeded the annual mean for the respective year and region. Median season measures (onset, offset and peak) and the established mean method were calculated for each virus. Results: An annual median 59 396 specimens were tested for RSV and 60 931 for influenza; 21–29% tested positive for RSV and 2–7% for influenza. National RSV activity began in April; region‐specific start weeks varied by 7 weeks. Duration of RSV activity did not vary widely by region (16–18 weeks in duration). National influenza activity started in June; region‐specific start weeks varied by 3 weeks. Duration of influenza epidemic activity varied more by region than that of RSV (7–13 weeks in duration). Conclusion: In Argentina, RSV and influenza activity overlapped during the winter months. RSV season tended to begin prior to the influenza season, and showed more variation in start week by region. Influenza seasons tended to vary more in duration than RSV seasons. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented in response to the article "Does influenza vaccination modify influenza disease severity? Data on older adults hospitalized with influenza during the 2012â€13 season in the United States" by C.S. Arriola and others in the 2015 issue.

The article discusses the identification of passive surveillance and household probes to determine chikungunya cases in Puerto Rico in 2014. Topics covered include the difference of chikungunya and dengue illnesses as well as the similarities in their symptoms. Also mentioned are the symptoms of chikungunya illness such as arthralgia and fever.

Background The World Health Organization (WHO) recommends case definitions for influenza surveillance that are also used in public health research, though their performance has not been assessed in many risk groups, including pregnant women in whom influenza may manifest differently. Â We evaluated the performance of symptom-based case definitions to detect influenza in a cohort of pregnant women in India, Peru, and Thailand. Methods In 2017, we contacted 4774 pregnant women twice a week during the influenza season to identify illnesses with new or worsened cough, runny nose, sore throat, difficulty breathing or myalgia, and collected data on other symptoms and nasal swabs for influenza rRT–PCR testing. To identify symptom predictors of influenza, we used multivariable logistic regression with forward selection of symptoms significant in univariate analysis after controlling for country, chronic conditions, influenza vaccination, and time from symptom onset to swab collection. We calculated sensitivity and specificity of each symptom, WHO respiratory illness case definitions and a case definition based on significant predictors from the multivariable model. Results Of 2431 eligible illness episodes among 1,716 participants, 142 (5.8%) were positive for influenza. Among individual symptoms, runny nose was most sensitive and measured fever ≥ 38° Celsius was most specific (Figure 1). In a multivariable model, measured fever ≥ 38° Celsius [adjusted odds ratio = 3.8, 95% confidence interval [CI] = 2.0–7.2], cough [2.7, CI 1.6–4.7], chills [2.2, CI 1.2–3.8], and myalgia [1.2, CI 2.2, 5.3] were independently associated with influenza illness. A case definition based on these four (measured fever, cough, chills or myalgia), was 91%-sensitive and 37% specific. Sensitivity and specificity of case definitions varied (Figure 2). Conclusion While a case definition based on one or more of fever, chills, cough or myalgia is highly-sensitive and moderately specific among pregnant women, case definitions requiring measured or subjective fever may miss many influenza cases making them sub-optimal for studies of burden or vaccine efficacy. The intended use of case definitions should be considered when evaluating the tradeoff between sensitivity and specificity. Disclosures All authors: No reported disclosures. [ABSTRACT FROM AUTHOR]