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ABSTRACT: Background: The COVID-19 pandemic has contributed to the widespread disruption of immunization services, including the postponement of mass vaccination campaigns. Methods: In May 2020, the World Health Organization and partners started monitoring COVID-19-related disruptions to mass vaccination campaigns against cholera, measles, meningitis A, polio, tetanus-diphtheria, typhoid, and yellow fever through the Immunization Repository Campaign Delay Tracker. The authors reviewed the number and target population of reported preventive and outbreak response vaccination campaigns scheduled, postponed, canceled, and reinstated at 4 time points: May 2020, December 2020, May 2021, and December 2021. Findings: Mass vaccination campaigns across all vaccines were disrupted heavily by COVID-19. In May 2020, 105 of 183 (57%) campaigns were postponed or canceled in 57 countries because of COVID-19, with an estimated 796 million postponed or missed vaccine doses. Campaign resumption was observed beginning in July 2020. In December 2021, 77 of 472 (16%) campaigns in 54 countries, mainly in the African Region, were still postponed or canceled because of COVID-19, with about 382 million postponed or missed vaccine doses. Interpretation: There is likely a high risk of vaccine-preventable disease outbreaks across all regions because of an increased number of susceptible persons resulting from the large-scale mass vaccination campaign postponement caused by COVID-19.

Introduction: As the world continues to urbanize, particularly in low- and middle-income countries, understanding the barriers and effective interventions to improve urban immunization equity is critical to achieving both Immunization Agenda 2030 targets and the Sustainable Development Goals. Approximately 25 million children missed one or more doses of the diphtheria, tetanus and pertussis (DTP3) vaccine in 2021 and it is estimated that close to 30% of the world’s children missing the first dose of DTP, known as zero-dose, live in urban and peri-urban settings. Methods: The aim of this research is to improve understanding of urban immunization equity through a qualitative review of mixed method studies, urban immunization strategies and funding proposals across more than 70 urban areas developed between 2016 and 2020, supported by Gavi, the Vaccine Alliance. These research studies and strategies created a body of evidence regarding the barriers to vaccination in urban settings and potential interventions relevant to low- and middle-income countries (LMICs) with a focus on the vaccination of urban poor, populations of concern and residents of informal settlements. Through the document review we identified common challenges to achieving equitable coverage in urban areas and mapped proposed interventions. Results: We identified 70 documents as part of the review and categorized results across (1) social determinants of health, (2) immunization service-delivery barriers and (3) quality of services. Barriers and solutions identified in the documents were categorized in these thematic areas, drawing information from results in more than 21 countries. Conclusion: Populations of concern such as migrants, refugees, residents of informal settlements and the urban poor face barriers to accessing care which include poor availability and quality of service. Example solutions proposed to these challenges include tailored delivery strategies, improved use of digital data collection and child-friendly services. More research is required on the efficacy of the proposed interventions identified and on gender-specific dynamics in urban poor areas affecting equitable immunization coverage.

The 2021 WHO and UNICEF Estimates of National Immunization Coverage (WUENIC) reported approximately 25 million under-vaccinated children in 2021, out of which 18 million were zero-dose children who did not receive even the first dose of a diphtheria-tetanus-pertussis-(DPT) containing vaccine. The number of zero-dose children increased by six million between 2019, the pre-pandemic year, and 2021. A total of 20 countries with the highest number of zero-dose children and home to over 75% of these children in 2021 were prioritized for this review. Several of these countries have substantial urbanization with accompanying challenges. This review paper summarizes routine immunization backsliding following the COVID-19 pandemic and predictors of coverage and identifies pro-equity strategies in urban and peri-urban settings through a systematic search of the published literature. Two databases, PubMed and Web of Science, were exhaustively searched using search terms and synonyms, resulting in 608 identified peer-reviewed papers. Based on the inclusion criteria, 15 papers were included in the final review. The inclusion criteria included papers published between March 2020 and January 2023 and references to urban settings and COVID-19 in the papers. Several studies clearly documented a backsliding of coverage in urban and peri-urban settings, with some predictors or challenges to optimum coverage as well as some pro-equity strategies deployed or recommended in these studies. This emphasizes the need to focus on context-specific routine immunization catch-up and recovery strategies to suit the peculiarities of urban areas to get countries back on track toward achieving the targets of the IA2030. While more evidence is needed around the impact of the pandemic in urban areas, utilizing tools and platforms created to support advancing the equity agenda is pivotal. We posit that a renewed focus on urban immunization is critical if we are to achieve the IA2030 targets.

We report a diphtheria outbreak mostly among children (median 12 years; range 4–26 years) of a religious minority in urban India. Case-fatality rate (15%, 19/124) was higher among unimmunized patients (relative risk 4.1, 95% CI 1.5–11.7). We recommend mandating and integrating immunization into school health programs to prevent reemergence.

Abstract Background In 2016, India reported 709 acute diarrheal disease (ADD) outbreaks (> 25% of all outbreaks). Tribal populations are at higher risk with 27% not having accessibility to safe drinking water and 75% households not having toilets. On June 26, 2017 Pedda-Gujjul-Thanda, a tribal village reported an acute diarrheal disease (ADD) outbreak. We investigated to describe the epidemiology, identify risk factors, and provide evidence-based recommendations. Methods We defined a case as ≥3 loose stools within 24 h in Pedda-Gujjul-Thanda residents from June 24–30, 2017. We identified cases by reviewing hospital records and house-to-house survey. We conducted a retrospective cohort study and collected stool samples for culture. We assessed drinking water supply and sanitation practices and tested water samples for faecal-contamination. Results We identified 191 cases (65% females) with median age 36 years (range 4–80 years) and no deaths. The attack-rate (AR) was 37% (191/512). Downhill colonies (located on slope of hilly terrains of the village) reported higher ARs (56%[136/243], p

Abstract Background Cutaneous anthrax in humans is associated with exposure to infected animals or animal products and has a case fatality rate of up to 20% if untreated. During May to June 2015, an outbreak of cutaneous anthrax was reported in Koraput district of Odisha, India, an area endemic for anthrax. We investigated the outbreak to identify risk factors and recommend control measures. Method We defined a cutaneous anthrax case as skin lesions (e.g., papule, vesicle or eschar) in a person residing in Koraput district with illness onset between February 1 and July 15, 2015. We established active surveillance through a house to house survey to ascertain additional cases and conducted a 1:2 unmatched case control study to identify modifiable risk factors. In case control study, we included cases with illness onset between May 1 and July 15, 2015. We defined controls as neighbours of case without skin lesions since last 3 months. Ulcer exudates and rolled over swabs from wounds were processed in Gram stain in the Koraput district headquarter hospital laboratory. Result We identified 81 cases (89% male; median age 38 years [range 5–75 years]) including 3 deaths (case fatality rate = 4%). Among 37 cases and 74 controls, illness was significantly associated with eating meat of ill cattle (OR: 14.5, 95% CI: 1.4–85.7) and with close handling of carcasses of ill animals such as burying, skinning, or chopping (OR: 342, 95% CI: 40.5–1901.8). Among 20 wound specimens collected, seven showed spore-forming, gram positive bacilli, with bamboo stick appearance suggestive of Bacillus anthracis. Conclusion Our investigation revealed significant associations between eating and handling of ill animals and presence of anthrax-like organisms in lesions. We immediately initiated livestock vaccination in the area, educated the community on safe handling practices and recommended continued regular anthrax animal vaccinations to prevent future outbreaks.

Despite advances in scaling up new vaccines in low- and middle-income countries, the global number of unvaccinated children has remained high over the past decade. We used 2000–2019 household survey data from 154 surveys representing 89 low- and middle-income countries to assess within-country, economic-related inequality in the prevalence of one-year-old children with zero doses of diphtheria–tetanus–pertussis (DTP) vaccine. Zero-dose DTP prevalence data were disaggregated by household wealth quintile. Difference, ratio, slope index of inequality, concentration index, and excess change measures were calculated to assess the latest situation and change over time, by country income grouping for 17 countries with high zero-dose DTP numbers and prevalence. Across 89 countries, the median prevalence of zero-dose DTP was 7.6%. Within-country inequalities mostly favored the richest quintile, with 19 of 89 countries reporting a rich–poor gap of ≥20.0 percentage points. Low-income countries had higher inequality than lower–middle-income countries and upper–middle-income countries (difference between the median prevalence in the poorest and richest quintiles: 14.4, 8.9, and 2.7 percentage points, respectively). Zero-dose DTP prevalence among the poorest households of low-income countries declined between 2000 and 2009 and between 2010 and 2019, yet economic-related inequality remained high in many countries. Widespread economic-related inequalities in zero-dose DTP prevalence are particularly pronounced in low-income countries and have remained high over the previous decade.

Scrub typhus is associated with outbreaks of acute encephalitis syndrome in Uttar Pradesh, India. A case-control study indicated that children residing, playing, or visiting fields; living with firewood stored indoors; handling cattle fodder; and practicing open defecation were at increased risk for scrub typhus. Communication messages should focus on changing these behaviors.

To determine the effects of school closure, we surveyed 214 households after a 1-week elementary school closure because of pandemic (H1N1) 2009. Students spent 77% of the closure days at home, 69% of students visited at least 1 other location, and 79% of households reported that adults missed no days of work to watch children.

Objectives Despite significant progress in childhood vaccination coverage globally, substantial inequality remains. Remote rural populations are recognised as a priority group for immunisation service equity. We aimed to link facility and individual data to examine the relationship between distance to services and immunisation coverage empirically, specifically using a rural population.Design and setting Retrospective cross-sectional analysis of facility data from the 2013–2014 Malawi Service Provision Assessment and individual data from the 2015–2016 Malawi Demographic and Health Survey, linking children to facilities within a 5 km radius. We examined associations between proximity to health facilities and vaccination receipt via bivariate comparisons and logistic regression models.Participants 2740 children aged 12–23 months living in rural areas.Outcome measures Immunisation coverage for the six vaccines included in the Malawi Expanded Programme on Immunization schedule for children under 1 year at time of study, as well as two composite vaccination indicators (receipt of basic vaccines and receipt of all recommended vaccines), zero-dose pentavalent coverage, and pentavalent dropout.Findings 72% (706/977) of facilities offered childhood vaccination services. Among children in rural areas, 61% were proximal to (within 5 km of) a vaccine-providing facility. Proximity to a vaccine-providing health facility was associated with increased likelihood of having received the rotavirus vaccine (93% vs 88%, p=0.004) and measles vaccine (93% vs 89%, p=0.01) in bivariate tests. In adjusted comparisons, how close a child was to a health facility remained meaningfully associated with how likely they were to have received rotavirus vaccine (adjusted OR (AOR) 1.63, 95% CI 1.13 to 2.33) and measles vaccine (AOR 1.62, 95% CI 1.11 to 2.37).Conclusion Proximity to health facilities was significantly associated with likelihood of receipt for some, but not all, vaccines. Our findings reiterate the vulnerability of children residing far from static vaccination services; efforts that specifically target remote rural populations living far from health facilities are warranted to ensure equitable vaccination coverage.

Background: Two suspected shellfish poisoning events were reported in Cuddalore District in Tamil Nadu, India, between January and April 2015. Objectives: The study was conducted to confirm the outbreaks and to identify the source and risk factors. Methods: For both outbreaks, a case was defined as a person with nausea, vomiting, or dizziness. Sociodemographic details and symptoms were noted down. Data were also collected in a standard 3-day food frequency questionnaire, along with a collection of clam samples. A case–control study was initiated in the April outbreak. Stool samples were collected from cases, and clam vendors were interviewed. Results: In an outbreak that happened in January, all the twenty people reported to be consumed clams were diagnosed as cases (100% attack rate, 100% exposure rate). In the April outbreak, we identified 199 cases (95% attack rate). In both outbreaks, the clams were identified as genus Meretrix meretrix. The most common reported symptoms were dizziness and vomiting. The clams heated and consumed within 30–60 min. No heavy metals or chemicals were detected in the clams, but assays for testing shellfish toxins were unavailable. All 64 selected cases reported clam consumption (100% exposure rate) as did 11 controls (17% exposure rate). Illness was associated with a history of eating of clams (odds ratio = 314, 95% confidence interval = 39–512). Of the six stool samples tested, all were culture negative for Salmonella, Shigella, and Vibrio cholerae. The water at both sites was contaminated with garbage and sewage. Conclusion: Coordinated and timely efforts by a multidisciplinary team of epidemiologists, marine biologists, and food safety officers led to the outbreaks' containment.

Background: Of 1115 measles outbreaks during 2015 in India, 61,255 suspected measles cases were reported. In 2016, a measles outbreak was reported at East and West Jaintia Hills districts in Meghalaya State, India. Objectives: The outbreak was investigated to describe the epidemiology, estimate vaccination coverage and vaccine effectiveness (VE), determine risk factors for the disease, and recommend control and prevention measures. Methods: A measles case was defined as new-onset fever with maculopapular rash occurring between May 1, 2016, and January 21, 2017, in a resident of East and West Jaintia Hills. Cases were identified by active and passive surveillance. Serum and urine samples were collected from cases with laboratory diagnosis for confirmation. A retrospective cohort study was conducted to estimate vaccination coverage, VE, and risk factors for the disease. Results: We identified 382 cases (51% female). The attack rate was 24% with three deaths. The case fatality rate was

Background: Acute diarrheal disease (ADD) outbreaks frequently occur in the Gangetic plains of Uttar Pradesh, India. In August 2017, Muzaffarpur village, Uttar Pradesh, reported an ADD outbreak. Objectives: Outbreak investigation was conducted to find out the epidemiology and to identify the risk factors. Methods: A 1:1 area-matched case–control study was conducted. Suspected ADD case was defined as ≥3 loose stools or vomiting within 24 h in a Muzaffarpur resident between August 7 and September 9, 2017. A control was defined as an absence of loose stools and vomiting in a resident between August 7 and September 9, 2017. A matched odds ratio (mOR) with 95% confidence intervals (CIs) was calculated. Drinking water was assessed to test for the presence of any contamination. Stool specimens were tested for Vibrio cholerae, and water samples were also tested for any fecal contamination and residual chlorine. Results: Among 70 cases (female = 60%; median age = 12 years, range = 3 months–70 years), two cases died and 35 cases were hospitalized. Area–A in Muzaffarpur had the highest attack rate (8%). The index case washed soiled clothes at well – A1 1 week before other cases occurred. Among 67 case–control pairs, water consumption from well–A1 (mOR: 43.00; 95% CI: 2.60–709.88) and not washing hands with soap (mOR: 2.87; 95% CI: 1.28–6.42) were associated with illness. All seven stool specimens tested negative for V. cholerae. All six water samples, including one from well–A1, tested positive for fecal contamination with

Background: Mandla District in Madhya Pradesh, India, reported a suspected cholera outbreak from Ghughri subdistrict on August 18, 2016. Objective: We investigated to determine risk factors and recommend control and prevention measures. Methods: We defined a case as >3 loose stools in 24 h in a Ghughri resident between July 20 and August 19, 2016. We identified cases by passive surveillance in health facilities and by a house-to-house survey in 28 highly affected villages. We conducted a 1:2 unmatched case–control study, collected stool samples for culture, and tested water sources for fecal contamination. Results: We identified 628 cases (61% female) from 96 villages; the median age was 27 years (range: 1 month–76 years). Illnesses began 7 days after rainfall with 259 (41%) hospitalizations and 14 (2%) deaths in people from remote villages who died before reaching a health facility; 12 (86%) worked in paddy fields. Illness was associated with drinking well water within paddy fields (odds ratio [OR] = 4.0, 95% confidence interval [CI] = 1.4–8.0) and not washing hands with soap after defecation (OR = 6.1, CI = 1.7–21). Of 34 stool cultures, 11 (34%) tested positive for Vibrio cholerae O1 Ogawa. We observed open defecation in affected villages around paddy fields. Of 16 tested water sources in paddy fields, eight (50%) were protected, but 100% had fecal contamination. Conclusion: We recommended education regarding pit latrine sanitation and safe water, especially in paddy fields, provision of oral rehydration solution in remote villages, and chlorine tablets for point-of-use treatment of drinking water.

In July 2015, we investigated a foodborne illness outbreak in Sithalikuppam and Verupachi villages, Cuddalore district, Tamil Nadu, among the political rally attendees to determine the risk factors for illness. We conducted a retrospective cohort study, calculated risk ratio for the food exposures, and cultured stool specimens. Of 55 rally attendees, we identified 36 (65%) case patients; 32 (89%) had diarrhea and 20 (56%) had vomiting. Median incubation period was 14 h. Eighty-nine percent (32/36) of those who ate lemon rice at dinner had illness compared to 21% (4/19) of those who did not (RR 4.2). Of the six nonattendees who ate leftovers on July 25, all ate only lemon rice and became ill. Stool cultures were negative for Salmonella, Shigella, and Vibrio species. Lemon rice was probably contaminated with enterotoxins such as from Bacillus cereus. Our findings highlighted need for community food safety education and importance of thorough outbreak investigations.

BACKGROUND: In May 2008, PulseNet detected a multistate outbreak of Salmonella enterica serotype Saintpaul infections. Initial investigations identified an epidemiologic association between illness and consumption of raw tomatoes, yet cases continued. In mid-June, we investigated two clusters of outbreak strain infections in Texas among patrons of Restaurant A and two establishments of Restaurant Chain B to determine the outbreak's source. METHODOLOGY/PRINCIPAL FINDINGS: We conducted independent case-control studies of Restaurant A and B patrons. Patients were matched to well controls by meal date. We conducted restaurant environmental investigations and traced the origin of implicated products. Forty-seven case-patients and 40 controls were enrolled in the Restaurant A study. Thirty case-patients and 31 controls were enrolled in the Restaurant Chain B study. In both studies, illness was independently associated with only one menu item, fresh salsa (Restaurant A: matched odds ratio [mOR], 37; 95% confidence interval [CI], 7.2-386; Restaurant B: mOR, 13; 95% CI 1.3-infinity). The only ingredient in common between the two salsas was raw jalapeño peppers. Cultures of jalapeño peppers collected from an importer that supplied Restaurant Chain B and serrano peppers and irrigation water from a Mexican farm that supplied that importer with jalapeño and serrano peppers grew the outbreak strain. CONCLUSIONS/SIGNIFICANCE: Jalapeño peppers, contaminated before arrival at the restaurants and served in uncooked fresh salsas, were the source of these infections. Our investigations, critical in understanding the broader multistate outbreak, exemplify an effective approach to investigating large foodborne outbreaks. Additional measures are needed to reduce produce contamination.