Global SARS-CoV-2 seroprevalence from January 2020 to April 2022: A systematic review and meta-analysis of standardized population-based studies.

BACKGROUND: Our understanding of the global scale of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection remains incomplete: Routine surveillance data underestimate infection and cannot infer on population immunity; there is a predominance of asymptomatic infections, and uneven access to diagnostics. We meta-analyzed SARS-CoV-2 seroprevalence studies, standardized to those described in the World Health Organization's Unity protocol (WHO Unity) for general population seroepidemiological studies, to estimate the extent of population infection and seropositivity to the virus 2 years into the pandemic. METHODS AND FINDINGS: We conducted a systematic review and meta-analysis, searching MEDLINE, Embase, Web of Science, preprints, and grey literature for SARS-CoV-2 seroprevalence published between January 1, 2020 and May 20, 2022. The review protocol is registered with PROSPERO (CRD42020183634). We included general population cross-sectional and cohort studies meeting an assay quality threshold (90% sensitivity, 97% specificity; exceptions for humanitarian settings). We excluded studies with an unclear or closed population sample frame. Eligible studies-those aligned with the WHO Unity protocol-were extracted and critically appraised in duplicate, with risk of bias evaluated using a modified Joanna Briggs Institute checklist. We meta-analyzed seroprevalence by country and month, pooling to estimate regional and global seroprevalence over time; compared seroprevalence from infection to confirmed cases to estimate underascertainment; meta-analyzed differences in seroprevalence between demographic subgroups such as age and sex; and identified national factors associated with seroprevalence using meta-regression. We identified 513 full texts reporting 965 distinct seroprevalence studies (41% low- and middle-income countries [LMICs]) sampling 5,346,069 participants between January 2020 and April 2022, including 459 low/moderate risk of bias studies with national/subnational scope in further analysis. By September 2021, global SARS-CoV-2 seroprevalence from infection or vaccination was 59.2%, 95% CI [56.1% to 62.2%]. Overall seroprevalence rose steeply in 2021 due to infection in some regions (e.g., 26.6% [24.6 to 28.8] to 86.7% [84.6% to 88.5%] in Africa in December 2021) and vaccination and infection in others (e.g., 9.6% [8.3% to 11.0%] in June 2020 to 95.9% [92.6% to 97.8%] in December 2021, in European high-income countries [HICs]). After the emergence of Omicron in March 2022, infection-induced seroprevalence rose to 47.9% [41.0% to 54.9%] in Europe HIC and 33.7% [31.6% to 36.0%] in Americas HIC. In 2021 Quarter Three (July to September), median seroprevalence to cumulative incidence ratios ranged from around 2:1 in the Americas and Europe HICs to over 100:1 in Africa (LMICs). Children 0 to 9 years and adults 60+ were at lower risk of seropositivity than adults 20 to 29 (p < 0.001 and p = 0.005, respectively). In a multivariable model using prevaccination data, stringent public health and social measures were associated with lower seroprevalence (p = 0.02). The main limitations of our methodology include that some estimates were driven by certain countries or populations being overrepresented. CONCLUSIONS: In this study, we observed that global seroprevalence has risen considerably over time and with regional variation; however, over one-third of the global population are seronegative to the SARS-CoV-2 virus. Our estimates of infections based on seroprevalence far exceed reported Coronavirus Disease 2019 (COVID-19) cases. Quality and standardized seroprevalence studies are essential to inform COVID-19 response, particularly in resource-limited regions.

Public health research priorities for WHO on COVID-19 in the South-East Asia Region: results of a prioritization survey.

BACKGROUND: Effectively addressing the coronavirus disease 2019 (COVID-19) pandemic caused by the new pathogen requires continuous generation of evidence to inform decision-making. Despite an unprecedented amount of research occurring globally, the need to identify gaps in knowledge and prioritize a research agenda that is linked to public health action is indisputable. The WHO South-East Asia Region (SEAR) is likely to have region-specific research needs. METHODS: We aimed to identify a priority research agenda for guiding the regional and national response to the COVID-19 pandemic in SEAR countries. An online, anonymous research prioritization exercise using recent WHO guidance was conducted among the technical staff of WHO's country and regional offices engaged with the national COVID-19 response during October 2020. They were each asked to contribute up to five priority research ideas across seven thematic areas. These research ideas were reviewed, consolidated and scored by a core group on six parameters: regional specificity, relevance to the COVID-19 response, feasibility within regional research capacity, time to availability for decision-making, likely impact on practice, and promoting equity and gender responsiveness. The total scores for individual suggestions were organized in descending order, and ideas in the upper tertile were considered to be of high priority. RESULTS: A total of 203 priority research ideas were received from 48 respondents, who were primarily research and emergency response focal points in country and regional offices. These were consolidated into 78 research ideas and scored. The final priority research agenda of 27 items covered all thematic areas-health system (n=10), public health interventions (n=6), disease epidemiology (n=5), socioeconomic and equity (n=3), basic sciences (n=1), clinical sciences (n=1) and pandemic preparedness (n=1). CONCLUSIONS: This exercise, a part of WHO's mandate to "shape the research agenda", can help build a research roadmap ensuring efficient use of limited resources. This prioritized research agenda can act as a catalyst for Member States to accelerate research that could impact the COVID-19 response in SEAR.

The Effects of Methamphetamine Use on the Sexual Lives of Gender and Sexually Diverse People in Dhaka, Bangladesh: A Qualitative Study.

Methamphetamine use has increased among gender and sexually diverse people in several countries, including Bangladesh. This study aimed to explore the effects of methamphetamine on the sexual lives of these people in Dhaka, Bangladesh. An exploratory qualitative study was conducted, comprising 30 in-depth interviews with gender and sexually diverse people including males having sex with males, male sex workers, and transgender women (hijra) under HIV intervention coverage. Ten key informant interviews were also conducted with individuals who have expertise in relevant disciplines such as drug use, harm reduction, and HIV and AIDS. Digitally recorded data were manually analyzed under the thematic analysis framework. Findings indicated that many participants reported that methamphetamine brought changes in their sexual lives such as increased sexual drive, engagement in group sex, the increased ability to perform serial sex, transactional sex, impulsive and coercive sex, initiation and switching of male-to-male sexual practices, and limited condom use. Key informants noted that there is a dearth of methamphetamine-related services in Bangladesh. Methamphetamine use was found to lead to diverse effects on the sexual lives of gender and sexually diverse people, thus making it a driving force for shaping sexual practices and, hence, sexual risks. Therefore, it is essential for policy-level stakeholders and program managers to consider the risks of methamphetamine use due to their negative ramifications on sexual health, including HIV risks.

Hepatitis C virus infections among clients attending an HIV testing and counseling center in Dhaka, Bangladesh.

The prevalence of hepatitis C virus (HCV) and genotypes among 965 individuals attending an HIV testing and counseling unit in Dhaka Bangladesh during Jan-Dec 2011 was determined. Anti-HCV antibody was detected in 4.4% individuals; the highest rate 37.8% was in people who inject drugs (PWID) followed by that in the general population (1.3%) and less than 1% in other populations. HCV RNA was detected in 2.7%. The most common genotype was genotype 3 (88.5%) followed by genotype 1 (11.5%). A national wide surveillance for HCV infection reaching all key populations is required to assess the countywide burden and to develop appropriate treatment strategies.

Effectiveness of a live oral human rotavirus vaccine after programmatic introduction in Bangladesh: A cluster-randomized trial.

BACKGROUND: Rotavirus vaccines are now globally recommended by the World Health Organization (WHO), but in early 2009 WHO's Strategic Advisory Group of Experts on Immunization reviewed available data and concluded that there was no evidence for the efficacy or effectiveness of a two-dose schedule of the human rotavirus vaccine (HRV; Rotarix) given early at 6 and 10 wk of age. Additionally, the effectiveness of programmatic rotavirus vaccination, including possible indirect effects, has not been assessed in low-resource populations in Asia. METHODS AND FINDINGS: In Bangladesh, we cluster-randomized (1:1) 142 villages of the Matlab Health and Demographic Surveillance System to include two doses of HRV with the standard infant vaccines at 6 and 10 wk of age or to provide standard infant vaccines without HRV. The study was initiated November 1, 2008, and surveillance was conducted concurrently at Matlab Diarrhoea Hospital and two community treatment centers to identify children less than 2 y of age presenting with acute rotavirus diarrhea (ARD) through March 31, 2011. Laboratory confirmation was made by enzyme immunoassay detection of rotavirus antigen in stool specimens. Overall effectiveness of the HRV vaccination program (primary objective) was measured by comparing the incidence rate of ARD among all children age-eligible for vaccination in villages where HRV was introduced to that among such children in villages where HRV was not introduced. Total effectiveness among vaccinees and indirect effectiveness were also evaluated. In all, 6,527 infants were age-eligible for vaccination in 71 HRV villages, and 5,791 in 71 non-HRV villages. In HRV villages, 4,808 (73.7%) infants received at least one dose of HRV. The incidence rate of ARD was 4.10 cases per 100 person-years in non-HRV villages compared to 2.8 per 100 person-years in HRV villages, indicating an overall effectiveness of 29.0% (95% CI, 11.3% to 43.1%). The total effectiveness of HRV against ARD among vaccinees was 41.4% (95% CI, 23.2% to 55.2%). The point estimate for total effectiveness was higher against ARD during the first year of life than during the second (45.2% versus 28.9%), but estimates for the second year of life lacked precision and did not reach statistical significance. Indirect effects were not detected. To check for bias in presentation to treatment facilities, we evaluated the effectiveness of HRV against acute diarrhea associated with enterotoxigenic Escherichia coli; it was 4.0% (95% CI, -46.5% to 37.1%), indicating that bias likely was not introduced. Thirteen serious adverse events were identified among recipients of HRV, but none were considered related to receipt of study vaccine. The main limitation of this study is that it was an open-label study with an observed-only control group (no placebo). CONCLUSIONS: The two-dose HRV rotavirus vaccination program significantly reduced medically attended ARD in this low-resource population in Asia. Protection among vaccinees was similar to that in other low-resource settings. In low-resource populations with high rotavirus incidence, large-scale vaccination across a wide population may be required to obtain the full benefit of rotavirus vaccination, including indirect effects. TRIAL REGISTRATION: ClinicalTrials.gov NCT00737503.

Sexually Transmitted Infections and Associated Risk Factors Among Street-Based and Residence-Based Female Sex Workers in Dhaka, Bangladesh.

BACKGROUND: Female sex workers (FSWs) in Bangladesh remain at elevated risk of sexually transmitted infections (STIs) although the human immunodeficiency virus (HIV) prevalence among them is low. Recent information on the burden and etiological diagnosis of STIs among them has been lacking. This study examines prevalence and risk behaviors of selected STIs among FSWs in Dhaka in 2014. METHODS: Between August and October 2014, a cross-sectional study was conducted among street-based and residence-based FSWs receiving HIV prevention services at 24 drop in centers in Dhaka. Participants underwent behavioral interview, clinical examination, and laboratory testing for selected STIs using cervical swabs and blood. RESULTS: The sample consisted of 371 streets and 329 residence FSWs. Prevalence of gonorrhea, chlamydia, and active syphilis were 5.1%, 4.6%, 1.3% in street FSWs and were 5.8%, 8.2%, and 0.6% for residence FSWs which are lower compared with the previously reported rates. The following factors were associated with having any STI: being ≤5 years in sex trade (odds ratio, 2.2; 95% confidence interval, 1.2-3.9; P < 0.01), and having a cervical discharge (odds ratio, 2.6, 95% confidence interval, 1.5-4.6; P < 0.01). Resistance to cefixime and azithromycin was observed for 1 and 3 Neisseria gonorrhoeae strains, respectively. CONCLUSIONS: Despite receiving HIV/STI prevention services, bacterial STIs remain prevalent among FSWs suggesting the need for more effective management of STIs. The guidelines for management of STIs need revision in view of the emerging resistance.

Noninterference of Rotavirus Vaccine With Measles-Rubella Vaccine at 9 Months of Age and Improvements in Antirotavirus Immunity: A Randomized Trial.

BACKGROUND: The burden of rotavirus morbidity and mortality is high in children aged <5 years in developing countries, and evaluations indicate waning protection from rotavirus immunization in the second year. An additional dose of rotavirus vaccine may enhance the immune response and lengthen the period of protection against disease, but coadministration of this dose should not interfere with immune responses to concurrently given vaccines. METHODS: A total of 480 9-month-old participants from Matlab, Bangladesh, were enrolled in a study with a primary objective to establish noninferiority of concomitant administration of measles-rubella vaccine (MR) and a third dose of human rotavirus vaccine (HRV; MR + HRV), compared with MR given alone. Secondary objectives included noninferiority of rubella antibody seroconversion and evaluating rotavirus IgA/IgG seroresponses in MR + HRV recipients. RESULTS: Two months after vaccination, 75.3% and 74.3% of MR + HRV and MR recipients, respectively, had seroprotective levels of measles virus antibodies; 100.0% and 99.6%, respectively, showed anti-rubella virus immunoglobulin G (IgG) seroprotection. In the MR + HRV group, antirotavirus immunoglobulin A and IgG seropositivity frequencies before vaccination (52.7% and 66.3%, respectively) increased to 69.6% and 88.3% after vaccination. CONCLUSIONS: Vaccine-induced measles and rubella antibody responses are not negatively affected by concomitant administration of HRV. The HRV dose increases antirotavirus serum antibody titers and the proportion of infants with detectable antirotavirus antibody. CLINICAL TRIALS REGISTRATION: NCT01700621.

Norovirus diarrhea in Bangladesh, 2010-2014: prevalence, clinical features, and genotypes.

Norovirus infections in diarrhea patients attending an urban and a rural hospital in Bangladesh were investigated. A total of 953 fecal specimens from both children and adults collected during 2010-2014 were tested for the presence of norovirus using real time PCR. One fourth (25%) of the specimens were positive for norovirus RNA which was identified both in children and adults. Norovirus was associated with short duration of diarrhea, high abdominal pain, and more moderate to severe dehydration when compared with rotavirus infections. Norovirus GII (69%) was the most prevalent genogroup followed by GI (18%), mixed GI/GII/GIV (11%), and GIV (2%). Among GII genogroup, GII.4 (42%) was the most prevalent genotype followed by GII.3 (21%), GII.6 (7%), GII.7 (6%), and GII.21 (6%). GII.4 and GII.3 strains were frequently identified (82% and 75%, respectively) in children <2 years of age and less commonly (16% and 15%) in adults more than 18 years of age. The present study reinforces the importance of norovirus-associated hospitalizations both in children and adults. The dynamic molecular epidemiology of norovirus requires routine strain surveillance to identify changes in prevailing strains. J. Med. Virol. 88:1742-1750, 2016. © 2016 Wiley Periodicals, Inc.

Effects of In-country and Cross-Border Mobility on Condom Use Among Transgender Women (hijras) in Bangladesh: A Cross-Sectional Study.

In Bangladesh transgender women (hijras) are thought to be highly mobile that may be an impediment to condom use. This cross-sectional study was conducted to determine the extent of mobility of hijras, in-country and cross-border, and whether mobility affects condom use in anal intercourse. Hijras ≥15 years of age, receiving services from the Global Fund supported HIV prevention program were enrolled. A behavioral questionnaire was administered and blood was tested for antibodies to HIV and syphilis. Of 889 hijras sampled, 41.3 % never traveled, 26.4 % traveled in-country and 32.3 % crossed the border in the last year. HIV and active syphilis was at 0.8 and 1.8 % respectively. Among hijras who crossed the border condom use was less likely in last anal intercourse (AOR 0.68; 95 % CI 0.48-0.96), and consistently with new (AOR 0.59; 95 % CI 0.34-1.01) and regular clients (AOR 0.45; 95 % CI 0.27-0.76) in the last week. This study concludes that in Bangladesh hijras are highly mobile and cross-border mobility negatively affects condom use.

Vulnerability of Bangladeshi street-children to HIV/AIDS: a qualitative study.

BACKGROUND: Children living on the streets are an underprivileged population of Bangladesh and are likely to be more vulnerable to STIs/HIV for their day-to-day risky behaviours and lifestyles. This study assessed the vulnerability of Bangladeshi street-children to HIV/AIDS using qualitative participatory methods. METHODS: This ethnographic participatory, qualitative study was conducted during February 2010- December 2011 among children aged 5-12 years, who live and/or work on the streets in Dhaka, the capital city of Bangladesh. Data were collected in three phases: (a) social mapping (n = 493), (b) participatory group discussions (n = 119), and (c) individual interviews (n = 36). RESULTS: Results showed that street-children were engaged in behaviour that entails risk of exposure to HIV/AIDS. They possessed poor knowledge of the transmission of disease and of the benefits of using condoms; most of them reported never using a condom. The experience of selling sex for money and a variety of sexual activities, like anal, vaginal and oral sex, were commonly reported. The children also reported that they were regular users of one or more types of drugs, including those taken by injection. CONCLUSIONS: The deplorable living conditions of street children, with no obvious rights or way out, make them highly vulnerable to HIV/AIDS. Urgent attention of the policy- makers to implement services addressing issues relating to social conditions, sexual health, and drug-use is warranted to prevent the possible epidemic of HIV/AIDS among this group of population.

Clade C HIV-1 isolates circulating in Southern Africa exhibit a greater frequency of dicysteine motif-containing Tat variants than those in Southeast Asia and cause increased neurovirulence.

BACKGROUND: HIV-1 Clade C (Subtype C; HIV-1C) is responsible for greater than 50% of infections worldwide. Unlike clade B HIV-1 (Subtype B; HIV-1B), which is known to cause HIV associated dementia (HAD) in approximately 15% to 30% of the infected individuals, HIV-1C has been linked with lower prevalence of HAD (0 to 6%) in India and Ethiopia. However, recent studies report a higher prevalence of HAD in South Africa, Zambia and Botswana, where HIV-1C infections predominate. Therefore, we examined whether Southern African HIV-1C is genetically distinct and investigated its neurovirulence. HIV-1 Tat protein is a viral determinant of neurocognitive dysfunction. Therefore, we focused our study on the variations seen in tat gene and its contribution to HIV associated neuropathogenesis. RESULTS: A phylogenetic analysis of tat sequences of Southern African (South Africa and Zambia) HIV isolates with those from the geographically distant Southeast Asian (India and Bangladesh) isolates revealed that Southern African tat sequences are distinct from Southeast Asian isolates. The proportion of HIV - 1C variants with an intact dicysteine motif in Tat protein (C30C31) was significantly higher in the Southern African countries compared to Southeast Asia and broadly paralleled the high incidence of HAD in these countries. Neuropathogenic potential of a Southern African HIV-1C isolate (from Zambia; HIV-1C 1084i), a HIV-1C isolate (HIV-1 IndieC1) from Southeast Asia and a HIV-1B isolate (HIV-1 ADA) from the US were tested using in vitro assays to measure neurovirulence and a SCID mouse HIV encephalitis model to measure cognitive deficits. In vitro assays revealed that the Southern African isolate, HIV-1C 1084i exhibited increased monocyte chemotaxis and greater neurotoxicity compared to Southeast Asian HIV-1C. In neurocognitive tests, SCID mice injected with MDM infected with Southern African HIV-1C 1084i showed greater cognitive dysfunction similar to HIV-1B but much higher than those exposed to Southeast Asian HIV - 1C. CONCLUSIONS: We report here, for the first time, that HIV-1C from Southern African countries is genetically distinct from Southeast Asian HIV-1C and that it exhibits a high frequency of variants with dicysteine motif in a key neurotoxic HIV protein, Tat. Our results indicate that Tat dicysteine motif determines neurovirulence. If confirmed in population studies, it may be possible to predict neurocognitive outcomes of individuals infected with HIV-1C by genotyping Tat.

A novel norovirus recombinant strain GII.4/GII.21 in Bangladesh, 2011.

We identified a novel inter-genotype recombinant norovirus strain, Dhaka85/2011/BGD, collected from a stool specimen of a nine-month-old infant who was hospitalized with diarrhea. Molecular investigation and phylogenetic analysis classified its RNA polymerase gene as GII.4-like, which commonly circulates in humans. The capsid gene was classified as GII.21-like, most likely originated from water. The discovery of this novel strain is an illustration of the enormous diversity among the norovirus strains, especially in developing countries and has important implications for future vaccine strategies.

Changing profile of rotavirus genotypes in Bangladesh, 2006-2012.

BACKGROUND: Rotavirus is the leading cause of severe diarrhea in infants and young children worldwide including Bangladesh. Unlike what was seen in high-income countries, the licensed rotavirus vaccines did not show high efficacy in Bangladeshi trials. We assessed rotavirus prevalence and genotypes in Bangladesh over six-year period to provide baseline information on the rotavirus burden and changing profile in the country. METHODS: This study was conducted from June 2006 to May 2012 in Matlab, Bangladesh. Group A rotaviruses were detected in stools collected from diarrhea patients by ELISA and genotyped using multiplex reverse transcription PCR followed by nucleotide sequencing. RESULTS: Of the 9678 stool samples, 20.3% were positive for rotavirus. The most predominant genotype was G1P[8] (22.4%), followed by G9P[8] (20.8%), G2P[4] (16.9%) and G12P[8] (10.4%). Mixed infections were detected in 14.2% of the samples. Emergence of an unusual strain, G9P[4] was documented during 2011-12. Several amino acid mismatches in the antigenic epitopes of VP7 and VP4 between Bangladeshi and the vaccine strains were identified. CONCLUSIONS: Our study provides important information on rotavirus genotypes that should be considered for the selection and introduction of rotavirus vaccines in Bangladesh.

Factors associated with relapse into drug use among male and female attendees of a three-month drug detoxification-rehabilitation programme in Dhaka, Bangladesh: a prospective cohort study.

BACKGROUND: To determine relapse rates and associated factors among people who use drugs (PWUDs) attending abstinence-oriented drug treatment clinics in Dhaka, Bangladesh. METHODS: A cohort of male and female PWUDs admitted to the 3-month drug detoxification-rehabilitation treatment programmes of three non-governmental organisation-run drug treatment clinics in Dhaka, Bangladesh were interviewed on admission and over the following 5 months, which included the first 2 months after discharge. The study subjects comprised 150 male and 110 female PWUDs who had been taking opiates/opioids, cannabis or other drugs (including sedatives) before admission, had provided informed consent and were aged ≥16 years. Interviews were conducted using semi-structured questionnaires at four time points; on admission, at discharge and at 1 and 2 months after discharge. Relapse rates were assessed by the Kaplan-Meier method. Factors associated with relapse on enrolment and after discharge were determined using the Cox proportional hazards regression model. RESULTS: A greater proportion of female than male subjects relapsed over the study period (71.9% versus 54.5%, p < 0.01). For men, baseline factors associated with relapse were living with other PWUDs (relative hazard ratio [RHR] = 2.27), living alone (RHR = 2.35) and not having sex with non-commercial partners (RHR = 2.27); whereas for women these were previous history of drug treatment (RHR = 1.94), unstable housing (RHR = 2.44), higher earnings (RHR = 1.89), preferring to smoke heroin (RHR = 3.62) and injecting buprenorphine/pethidine (RHR = 3.00). After discharge, relapse for men was associated with unstable housing (RHR = 2.78), living alone (RHR = 3.69), higher earnings (RHR = 2.48) and buying sex from sex workers (RHR = 2.29). Women' relapses were associated with not having children to support (RHR = 3.24) and selling sex (RHR = 2.56). CONCLUSIONS: The relapse rate was higher for female PWUDs. For both male and female subjects the findings highlight the importance of stable living conditions. Additionally, female PWUDs need gender-sensitive services and active efforts to refer them for opioid substitution therapy, which should not be restricted only to people who inject drugs.

Early detection of pandemic (H1N1) 2009, Bangladesh.

To explore Bangladesh's ability to detect novel influenza, we examined a series of laboratory-confirmed pandemic (H1N1) 2009 cases. During June-July 2009, event-based surveillance identified 30 case-patients (57% travelers); starting July 29, sentinel sites identified 252 case-patients (1% travelers). Surveillance facilitated response weeks before the spread of pandemic (H1N1) 2009 infection to the general population.

Influenza-associated mortality in 2009 in four sentinel sites in Bangladesh.

OBJECTIVE: To estimate influenza-associated mortality in Bangladesh in 2009. METHODS: In four hospitals in Bangladesh, respiratory samples were collected twice a month throughout 2009 from inpatients aged < 5 years with severe pneumonia and from older inpatients with severe acute respiratory infection. The samples were tested for influenza virus ribonucleic acid (RNA) using polymerase chain reaction. The deaths in 2009 in five randomly selected unions (the smallest administrative units in Bangladesh) in each hospital's catchment area were then investigated using formal records and informal group discussions. The deaths of those who had reportedly died within 14 days of suddenly developing fever with cough and/or a sore throat were assumed to be influenza-associated. The rate of such deaths in 2009 in each of the catchment areas was then estimated from the number of apparently influenza-associated deaths in the sampled unions, the proportion of the sampled inpatients in the local hospital who tested positive for influenza virus RNA, and the estimated number of residents of the sampled unions. FINDINGS: Of the 2500 people known to have died in 2009 in all 20 study unions, 346 (14%) reportedly had fever with cough and/or sore throat within 14 days of their deaths. The estimated mean annual influenza-associated mortality in these unions was 11 per 100,000 population: 1.5, 4.0 and 125 deaths per 100,000 among those aged < 5, 5-59 and > 59 years, respectively. CONCLUSION: The highest burden of influenza-associated mortality in Bangladesh in 2009 was among the elderly.

Incidence of influenza-like illness and severe acute respiratory infection during three influenza seasons in Bangladesh, 2008-2010.

OBJECTIVE: To determine how much influenza contributes to severe acute respiratory illness (SARI), a leading cause of death in children, among people of all ages in Bangladesh. METHODS: Physicians obtained nasal and throat swabs to test for influenza virus from patients who were hospitalized within 7 days of the onset of severe acute respiratory infection (SARI) or who consulted as outpatients for influenza-like illness (ILI). A community health care utilization survey was conducted to determine the proportion of hospital catchment area residents who sought care at study hospitals and calculate the incidence of influenza using this denominator. FINDINGS: The estimated incidence of SARI associated with influenza in children < 5 years old was 6.7 (95% confidence interval, CI: 0-18.3); 4.4 (95% CI: 0-13.4) and 6.5 per 1000 person-years (95% CI: 0-8.3/1000) during the 2008, 2009 and 2010 influenza seasons, respectively. The incidence of SARI in people aged ≥ 5 years was 1.1 (95% CI: 0.4-2.0) and 1.3 (95% CI: 0.5-2.2) per 10,000 person-years during 2009 and 2010, respectively. The incidence of medically attended, laboratory-confirmed seasonal influenza in outpatients with ILI was 10 (95% CI: 8-14), 6.6 (95% CI: 5-9) and 17 per 100 person-years (95% CI: 13-22) during the 2008, 2009 and 2010 influenza seasons, respectively. CONCLUSION: Influenza-like illness is a frequent cause of consultation in the outpatient setting in Bangladesh. Children aged less than 5 years are hospitalized for influenza in greater proportions than children in other age groups.

Resumen OBJETIVO: Determinar en qué medida contribuye la gripe a la enfermedad respiratoria aguda grave (ERAG), una de las principales causas de muerte infantil, en personas de todas las edades en Bangladesh. MÉTODOS: Los médicos tomaron muestras de exudado nasal y faríngeo para realizar la prueba del virus de la gripe en pacientes que estuvieron hospitalizados en los 7 días posteriores al inicio de la infección respiratoria agua grave (IRAG) o que acudieron a consulta como pacientes ambulatorios por síndrome gripal (SG). Se llevó a cabo un estudio sobre el uso de la asistencia sanitaria comunitaria para determinar la proporción de residentes del área de cobertura del hospital que solicitaron asistencia médica en hospitales pertenecientes al estudio y se calculó la incidencia de la gripe con este denominador. RESULTADOS: La incidencia estimada de la IRAG asociada con la gripe en niños menores de 5 años fue del 6,7 (95% de intervalo de confianza, IC: 0-18,3); 4,4 (95% IC: 0-13,4) y 6,5 por 1000 años-persona (95% IC: 0-8,3/1000) durante las temporadas de gripe de 2008, 2009 y 2010, respectivamente. La incidencia de la IRAG en las personas con una edad igual o superior a 5 años fue del 1,1 (95% IC: 0,4- 2,0) y 1,3 (95% IC: 0,5-2,2) por 10 000 años-persona durante 2009 y 2010, respectivamente. La incidencia de la gripe de temporada tratada médicamente y confirmada en laboratorio en pacientes ambulatorios con SG fue de 10 (95% IC: 8-14); 6,6 (95% IC: 5-9) y 17 por 100 años-persona (95% IC: 13-22/1000) durante las temporadas de gripe de 2008, 2009 y 2010, respectivamente. CONCLUSIÓN: El síndrome gripal es una causa frecuente de consulta en los centros ambulatorios en Bangladesh. La proporción de niños menores de 5 años hospitalizados por gripe es mayor que la de niños en otros grupos de edad.

Résumé OBJECTIF: Déterminer l'impact de la grippe sur le syndrome respiratoire aigu sévère (SRAS), une cause majeure de la mortalité chez les enfants, chez les personnes de tous les âges au Bangladesh. MÉTHODES: Les médecins ont obtenu des écouvillons de prélèvement de nez et de gorge afin de tester le virus de la grippe chez des patients qui avaient été hospitalisés dans les 7 jours suivants l'apparition de l'infection respiratoire aiguë sévère (SRAS) ou qui avaient eu une consultation déambulatoire pour un syndrome de type grippal (STG). Une enquête sur l'utilisation des soins de santé communautaires a été effectuée afin de définir la proportion des riverains de la circonscription hospitalière, qui avaient reçu des soins dans les hôpitaux universitaires, et afin de calculer l'incidence de la grippe à l'aide de ce dénominateur. RÉSULTATS: L'estimation de l'incidence du SRAS associé à la grippe chez les enfants de moins de 5 ans était de 6,7 (intervalle de confiance de 95%, IC: 0-18.3); de 4,4 (IC de 95%: 0-13.4) et de 6,5 pour 1 000 personnes-années (IC de 95%: 0-8.3/1000) lors des saisons de la grippe de 2008, 2009 et 2010, respectivement. L'incidence du SRAS chez les personnes âgées de plus de 5 ans était de 1,1 (IC de 95%: 0.4-2.0) et 1,3 (IC de 95%: 0.5-2.2) pour 10 000 personnes-années en 2009 et 2010, respectivement. L'incidence de la grippe saisonnière traitée médicalement et confirmée en laboratoire chez les patients en consultation ambulatoire souffrant du STG était de 10 (IC de 95%: 8-14), 6,6 (IC de 95%: 5-9) et de 17 pour 100 personnes-années (IC de 95%: 13-22) lors des saisons de la grippe de 2008, 2009 et 2010, respectivement. CONCLUSION: Le syndrome de type grippal est une cause fréquente de consultation dans la configuration de la consultation ambulatoire au Bangladesh. Les enfants de moins de 5 ans sont hospitalisés pour la grippe dans des proportions supérieures aux enfants des autres groupes d'âge.

Early epidemiological investigations: World Health Organization UNITY protocols provide a standardized and timely international investigation framework during the COVID-19 pandemic.

BACKGROUND: The declaration of Coronavirus disease 2019 (COVID-19) as a Public Health Emergency of International Concern (PHEIC) on 30 January 2020 required rapid implementation of early investigations to inform appropriate national and global public health actions. METHODS: The suite of existing pandemic preparedness generic epidemiological early investigation protocols was rapidly adapted for COVID-19, branded the 'UNITY studies' and promoted globally for the implementation of standardized and quality studies. Ten protocols were developed investigating household (HH) transmission, the first few cases (FFX), population seroprevalence (SEROPREV), health facilities transmission (n = 2), vaccine effectiveness (n = 2), pregnancy outcomes and transmission, school transmission, and surface contamination. Implementation was supported by WHO and its partners globally, with emphasis to support building surveillance and research capacities in low- and middle-income countries (LMIC). RESULTS: WHO generic protocols were rapidly developed and published on the WHO website, 5/10 protocols within the first 3 months of the response. As of 30 June 2021, 172 investigations were implemented by 97 countries, of which 62 (64%) were LMIC. The majority of countries implemented population seroprevalence (71 countries) and first few cases/household transmission (37 countries) studies. CONCLUSION: The widespread adoption of UNITY protocols across all WHO regions indicates that they addressed subnational and national needs to support local public health decision-making to prevent and control the pandemic.

Transmission of SARS-CoV-2 in standardised first few X cases and household transmission investigations: A systematic review and meta-analysis.

We aimed to estimate the household secondary infection attack rate (hSAR) of SARS-CoV-2 in investigations aligned with the WHO Unity Studies Household Transmission Investigations (HHTI) protocol. We conducted a systematic review and meta-analysis according to PRISMA 2020 guidelines. We searched Medline, Embase, Web of Science, Scopus and medRxiv/bioRxiv for "Unity-aligned" First Few X cases (FFX) and HHTIs published 1 December 2019 to 26 July 2021. Standardised early results were shared by WHO Unity Studies collaborators (to 1 October 2021). We used a bespoke tool to assess investigation methodological quality. Values for hSAR and 95% confidence intervals (CIs) were extracted or calculated from crude data. Heterogeneity was assessed by visually inspecting overlap of CIs on forest plots and quantified in meta-analyses. Of 9988 records retrieved, 80 articles (64 from databases; 16 provided by Unity Studies collaborators) were retained in the systematic review; 62 were included in the primary meta-analysis. hSAR point estimates ranged from 2% to 90% (95% prediction interval: 3%-71%; I 2 = 99.7%); I 2 values remained >99% in subgroup analyses, indicating high, unexplained heterogeneity and leading to a decision not to report pooled hSAR estimates. FFX and HHTI remain critical epidemiological tools for early and ongoing characterisation of novel infectious pathogens. The large, unexplained variance in hSAR estimates emphasises the need to further support standardisation in planning, conduct and analysis, and for clear and comprehensive reporting of FFX and HHTIs in time and place, to guide evidence-based pandemic preparedness and response efforts for SARS-CoV-2, influenza and future novel respiratory viruses.