SARS-CoV-2 serosurvey among adults involved in healthcare and health research in Guinea-Bissau, West Africa.

OBJECTIVES: Many African countries have reported fewer COVID-19 cases than countries elsewhere. By the end of 2020, Guinea-Bissau, West Africa, had <2500 PCR-confirmed cases corresponding to 0.1% of the ∼1.8 million national population. We assessed the prevalence of SARS-CoV-2 antibodies in urban Guinea-Bissau to help guide the pandemic response in Guinea-Bissau. STUDY DESIGN: Cross-sectional assessment of SARS-CoV-2 antibody in a cohort of staff at the Bandim Health Project. METHODS: We measured IgG antibodies using point-of-care rapid tests among 140 staff and associates at a biometric research field station in Bissau, the capital of Guinea-Bissau, during November 2020. RESULTS: Of 140 participants, 25 (18%) were IgG-positive. Among IgG-positives, 12 (48%) reported an episode of illness since the onset of the pandemic. Twenty-five (18%) participants had been PCR-tested between May and September; 7 (28%) had been PCR-positive. Four of these seven tested IgG-negative in the present study. Five participants reported that somebody had died in their house, corresponding crudely to an annual death rate of 4.5/1000 people; no death was attributed to COVID-19. Outdoor workers had a lower prevalence of IgG-positivity. CONCLUSIONS: In spite of the low official number of COVID-19 cases, our serosurvey found a high prevalence of IgG-positivity. Most IgG-positives had not been ill. The official number of PCR-confirmed COVID-19 cases has thus grossly underestimated the prevalence of COVID-19 during the pandemic. The observed overall mortality rate in households of Bandim Health Project employees was not higher than the official Guinean mortality rate of 9.6/1000 people.

Coverage and factors associated with receiving campaign polio vaccines in an urban population in Guinea-Bissau.

BACKGROUND: Polio eradication campaigns are intended to complement routine immunization. Studies addressing factors associated with campaign coverage are warranted to identify children missed by campaigns. METHODS: Bandim Health Project runs demographic surveillance with registration of routine immunization and campaign participation data in urban Guinea-Bissau. We assessed coverage and factors associated with receiving campaign polio vaccines in children aged 0-35 months in two polio eradication campaigns conducted in 2017 and 2018 using univariate and multivariate regression models. RESULTS: Campaign coverage reached 84% in 2017 and 88% in 2018. We found lower coverage among children of young and not formally educated mothers in univariate analyses; Children <9 months and Fula children had lower campaign coverage in both univariate and multivariate analyses. CONCLUSIONS: To increase campaign coverage in urban Guinea-Bissau attention may be directed at informing young mothers, mothers of young children, mothers without formal education, and the Fula ethnic group about campaigns.

BCG scarring and improved child survival: a combined analysis of studies of BCG scarring.

Bacillus Calmette-Guérin (BCG) vaccine against tuberculosis (TB) is recommended at birth in TB-endemic areas. Currently, BCG vaccination programmes use "BCG vaccination coverage by 12 months of age" as the performance indicator. Previous studies suggest that BCG-vaccinated children, who develop a scar, have better overall survival compared with BCG-vaccinated children, who do not develop a scar. We summarized the available studies of BCG scarring and child survival. A structured literature search for studies with original data and analysis of BCG scarring and mortality were performed. Combined analyses on the effect of BCG scarring on overall mortality. We identified six studies covering seven cohorts, all from Guinea-Bissau, West Africa, with evaluation of BCG scarring amongst BCG-vaccinated children and follow-up for mortality. Determinants of BCG scarring were BCG strain, intradermal injection route, size of injection wheal, and co-administered vaccines and micronutrients. In a combined analysis, having a BCG scar vs. no BCG scar was associated with a mortality rate ratio (MRR) of 0.61 (95% CI: 0.51-0.74). The proportion with a BCG scar varied from 52 to 93%; the estimated effect of a BCG scar was not associated with the scar prevalence. The effect was strongest in the first (MRR = 0.48 (0.37-0.62)) and second (MRR = 0.63 (0.44-0.92)) year of life, and in children BCG-vaccinated in the neonatal period (MRR = 0.45 (0.36-0.55)). The effect was not explained by protection against TB. Confounding and genetic factors are unlikely to explain the strong association between BCG scarring and subsequent survival. Including "BCG scar prevalence" as a BCG vaccination programme performance indicator should be considered. The effect of revaccinating scar-negative children should be studied.

Research protocol of two concurrent cluster-randomized trials: Real-life Effect of a CAMPaign with Measles Vaccination (RECAMP-MV) and Real-life Effect of a CAMPaign with Oral Polio Vaccination (RECAMP-OPV) on mortality and morbidity among children in rural Guinea-Bissau.

BACKGROUND: Measles and oral polio vaccinations may reduce child mortality to an extent that cannot be explained by prevention of measles and polio infections; these vaccines seem to have beneficial non-specific effects. In the last decades, billions of children worldwide have received measles vaccine (MV) and oral polio vaccine (OPV) through campaigns. Meanwhile the under-five child mortality has declined. Past MV and OPV campaigns may have contributed to this decline, even in the absence of measles and polio infections. However, cessation of these campaigns, once their targeted infections are eradicated, may reverse the decline in the under-five child mortality. No randomized trial has assessed the real-life effect of either campaign on child mortality and morbidity. We present the research protocol of two concurrent trials: RECAMP-MV and RECAMP-OPV. METHODS: Both trials are cluster-randomized trials among children registered in Bandim Health Project's rural health and demographic surveillance system throughout Guinea-Bissau. RECAMP-MV is conducted among children aged 9-59 months and RECAMP-OPV is conducted among children aged 0-8 months. We randomized 222 geographical clusters to intervention or control clusters. In intervention clusters, children are offered MV or OPV (according to age at enrolment) and a health check-up. In control clusters, children are offered only a health check-up. Enrolments began in November 2016 (RECAMP-MV) and March 2017 (RECAMP-OPV). We plan 18,000 enrolments for RECAMP-MV with an average follow-up period of 18 months and 10,000 enrolments for RECAMP-OPV with an average follow-up period of 10 months. Data collection is ongoing. The primary outcome in both trials is non-accidental death or non-accidental first non-fatal hospitalization with overnight stay (composite outcome). Secondary outcomes are: non-accidental death, repeated non-fatal hospitalizations with overnight stay, cause-specific primary outcome, outpatient visit, and illness. We obtained ethical approval from Guinea-Bissau and consultative approval from Denmark. DISCUSSION: Cluster randomization and minimum risk of loss to follow-up are strengths, and no placebo a limitation. Our trials challenge the understanding that MV and OPV only prevent measles and polio, and that once both infections are eradicated, campaigns with MV and OPV can be phased out without negative implications on child health and survival. TRIAL REGISTRATION: NCT03460002.

Early BCG Vaccination, Hospitalizations, and Hospital Deaths: Analysis of a Secondary Outcome in 3 Randomized Trials from Guinea-Bissau.

Background: This study was performed to examine the effects of early BCG vaccination on the risk, cause, and severity of infant hospitalizations. The analysis included 3 trials randomizing low-weight neonates to early BCG vaccination (intervention) versus no BCG vaccination (usual practice in low-weight neonates, control), with hospitalizations as secondary outcome. Methods: Hospitalization data were collected at the pediatric ward of the National Hospital. Effects of BCG vaccination on hospitalization risk were assessed in Cox models providing overall and major disease-group incidence rate ratios (IRRs). Severity was assessed by means of in-hospital case-fatality rates and compared by group as cohort study risk ratios (RRs). Results: Among 6583 infants (3297 in BCG group, 3286 controls), there were 908 infant hospitalizations (450 BCG, 458 controls) and 135 in-hospital deaths (56 BCG, 79 controls). The neonatal (28 days), 6-week, and infant (1-year) BCG versus control hospitalization IRRs were 0.97 (95% confidence interval [CI], .72-1.31), 0.95 (.73-1.24), and 0.96 (.84-1.10). Corresponding BCG versus control case-fatality rate RRs were 0.58 (95% CI, .35-.94), 0.56 (.35-.90), and 0.72 (.53-.99). BCG vaccination tended to reduce neonatal and infant sepsis hospitalization rates (IRR, 0.75 [95% CI, .50-1.13] and 0.78 [.55-1.11], respectively), and it reduced the neonatal in-hospital sepsis mortality rate (RR, 0.46; 95% CI, .22-.98). There were no confirmed hospitalizations for tuberculosis. Conclusions: BCG vaccination did not affect hospitalization rates but reduced in-hospital mortality rates significantly, primarily by preventing fatal cases of sepsis. The observed beneficial effects of BCG on the in-hospital mortality rate were entirely nonspecific. Clinical Trials Registration: NCT00146302, NCT00168610, and NCT00625482.

Non-specific effects of childhood vaccinations - A case control study nested into a Health and Demographic Surveillance System in rural Burkina Faso.

INTRODUCTION: Previous studies in African countries have been suggestive of non-specific effects (NSE) of vaccination on child survival. Live vaccines (e.g. measles, MV) have been found to reduce child mortality while inactivated vaccines (e.g. diphtheria-tetanus-pertussis, DTP) have been associated with increased mortality; NSE were often found to be sex-specific. METHODS: A case-control study nested into the Health and Demographic Surveillance System (HDSS) cohort of the Centre de Recherche en Santé de Nouna (CRSN) was conducted in northwestern Burkina Faso. A total of 3,010 children born in 2009-11, were included in the study, 375 cases and 2635 age and village matched controls. The main outcome measures were the mortality odds ratios for vaccinated versus unvaccinated children by antigen. The main outcome measures were the mortality odds ratios for vaccinated versus unvaccinated children by antigen. RESULTS: Most deaths occurred in late infancy, and there were significantly more deaths in males as compared to females (OR 1.29, CI 1.04-1.60). Overall, there was no statistically significant association between vaccine status and mortality. However, among children in the age group 2-8 months, there was a consistent sex-differential pattern for all doses of oral polio vaccine combined with pentavalent vaccine (OPV + Penta), with the vaccines being associated with lower mortality in boys, but not in girls. Routine MV + yellow fever vaccine was associated with reduced mortality, but only before mass vaccination campaigns with meningitis and measles vaccines took place. CONCLUSIONS: The findings of this study provide further support on the existence of NSE of childhood vaccinations in a large population of rural Burkina Faso. More randomized controlled trials are needed to confirm these observations.

Campaigns with oral polio vaccine may lower mortality and create unexpected results.

Three studies from Guinea-Bissau found conflicting effects of OPV-at-birth (OPV0) on child survival. One study from 2004 suggested excess male mortality among children receiving OPV0 compared with children receiving NoOPV0 during a period of shortage of OPV. However, two subsequent studies showed beneficial effects of OPV0. In 2004, two national OPV-campaigns had been conducted in Guinea-Bissau. In a reanalysis of the 2004-study, in a survival analysis the age-adjusted mortality rate of study participants was 67% (95% CI=42-81%) lower after the OPV-campaigns than before the campaigns. In the OPV0 group only 22% (655/3031 person-years (pyrs)) of follow-up time was "after" the OPV-campaigns whereas 55% (473/859 pyrs) of the time in the NoOPV0 group was post-campaign (p<0.0001, Chi2). Censoring for OPV-campaigns in the original study removed excess male mortality and made the three studies more homogeneous. Overall, there is now considerable evidence that OPV, like other live vaccines, has important beneficial non-specific effects.

A general measles vaccination campaign in urban Guinea-Bissau: Comparing child mortality among participants and non-participants.

BACKGROUND: Measles vaccination campaigns targeting children aged 9-59months are conducted every three years in Guinea-Bissau. Studies have demonstrated beneficial non-specific effects of measles vaccine. We compared mortality one year after the December 2012 measles vaccination campaign in Bissau city for children who received campaign measles vaccine with children who did not receive campaign measles vaccine. METHODS: Field workers from Bandim Health Project registered all children living in the Bandim Health Project's study area who received measles vaccination at the campaign posts. Children not seen during the campaign were visited at home and campaign participation status was assessed. We compared mortality rates of participants vs. non-participants in Cox regression models. RESULTS: 5633 children aged 9-59months (85%) received campaign measles vaccination and 1006 (15%) did not. During the subsequent year 16 children died. Adjusted for background factors, the hazard ratio (HR) comparing measles vaccinated versus unvaccinated was 0.28 (95% CI: 0.10-0.77). The benefit was larger for girls (HR: 0.17 (0.05-0.59)) and for children who had received routine measles vaccine before the campaign (HR: 0.15 (0.04-0.63)). CONCLUSIONS: We found indications of strong beneficial non-specific effects of receiving measles vaccine during the 2012 campaign, especially for girls and children with previous routine measles vaccination. Measles vaccination campaigns may be an effective way of improving child survival.

Household experience and costs of seeking measles vaccination in rural Guinea-Bissau.

OBJECTIVES: Children younger than 12 months of age are eligible for childhood vaccines through the public health system in Guinea-Bissau. To limit open vial wastage, a restrictive vial opening policy has been implemented; 10-dose measles vaccine vials are only opened if six or more children aged 9-11 months are present at the vaccination post. Consequently, mothers who bring their child for measles vaccination can be told to return another day. We aimed to describe the household experience and estimate household costs of seeking measles vaccination in rural Guinea-Bissau. METHODS: Within a national sample of village clusters under demographic surveillance, we interviewed mothers of children aged 9-21 months about their experience with seeking measles vaccination. From information about time and money spent, we calculated household costs of seeking measles vaccination. RESULTS: We interviewed mothers of 1308 children of whom 1043 (80%) had sought measles vaccination at least once. Measles vaccination coverage was 70% (910/1308). Coverage decreased with increasing distance to the health centre. On average, mothers who had taken their child for vaccination took their child 1.4 times. Mean costs of achieving 70% coverage were 2.04 USD (SD 3.86) per child taken for vaccination. Half of the mothers spent more than 2 h seeking vaccination and 11% spent money on transportation. CONCLUSIONS: We found several indications of missed opportunities for measles vaccination resulting in suboptimal coverage. The household costs comprised 3.3% of the average monthly income and should be taken into account when assessing the costs of delivering vaccinations.

Different effects of BCG strains - A natural experiment evaluating the impact of the Danish and the Russian BCG strains on morbidity and scar formation in Guinea-Bissau.

BACKGROUND: Different Bacillus Calmette-Guerin (BCG) vaccine strains may have different non-specific effects. We assessed the effect of two BCG strains (Danish and Russian) on childhood morbidity and BCG scarification in Guinea-Bissau. METHODS: During 2011-2013, infants in the Bandim Health Project's urban study area received the Danish or Russian BCG in a natural experiment. Health center consultations were registered at point of care and scar status and size at age 4½ months. We assessed the effect of strain on consultation rates between vaccination and age 45days in Cox proportional hazards models. Scar prevalence and size were compared using binomial regression and ranksum tests. RESULTS: Among 1206 children, 18% received Danish BCG (n=215) and 82% Russian BCG (n=991). The adjusted hazard ratio (aHR) for consultations was 0.94 (95% CI 0.60-1.46) for Danish BCG compared with Russian BCG. Girls vaccinated with Danish BCG tended to have lower consultation rates compared with girls vaccinated with Russian BCG (aHR 0.56 (0.25-1.24)), whereas the effect was opposite for boys (aHR 1.24 (0.74-2.11)), p=0.09. Children vaccinated with Danish BCG were more likely to develop a scar (97%) than children vaccinated with Russian BCG (87%), the relative risk (RR) being 1.11 (1.06-1.16). The effect was stronger in girls, and BCG scar size was larger among infants vaccinated with the Danish strain. CONCLUSION: BCG strain influences scar prevalence and scar size, and may have sex differential effects on morbidity. BCG strains are currently used interchangeably, but BCG scarring has been linked to subsequent survival. Hence, more research into the health effects of different BCG strains is warranted. Small adjustments of BCG production could potentially lower childhood morbidity and mortality at low cost.

Neonatal vitamin A supplementation associated with increased atopy in girls.

BACKGROUND: Neonatal vitamin A supplementation (NVAS) is currently being considered as policy in countries at risk of deficiency. A previous study suggested that NVAS may be associated with increased atopy. We examined the effect of NVAS on atopy by conducting long-term follow-up of a previous randomized controlled trial in Guinea-Bissau. METHODS: In 2002-2004, we randomized 4345 normal birthweight neonates to NVAS (50 000 IU retinyl palmitate) or placebo together with their Bacillus Calmette-Guérin vaccination. In 2013, we visited the 1692 (39%) children now aged 8-10 years who were still living in the study area, and 1478 (87%) were found at home. Provided consent, a skin prick test was performed, and history of allergic symptoms was recorded. Associations of NVAS and atopy (defined as skin prick test reaction of ≥3 mm) were analysed using binomial regression. RESULTS: Of the 1430 children with a valid skin prick test, 228 (16%) were positive (more boys (20%) than girls (12%), P-value < 0.0001). NVAS did not increase the overall risk of atopy (RR 1.10 [95% CI 0.87-1.40]). However, NVAS was associated with significantly increased risk among females (RR 1.78 [1.17-2.72]) but not among males (0.86 [0.64-1.15], P-value for interaction between NVAS and gender = 0.005). Furthermore, NVAS was associated with increased risk of wheezing among females (RR 1.80 [1.03-3.17], but not among males, P-value for interaction = 0.05). CONCLUSION: The study corroborated previous observations; NVAS was associated with increased risk of atopy and wheezing, in this study only among females. Further studies on NVAS and atopy are warranted.

Mid-upper-arm-circumference and mid-upper-arm circumference z-score: the best predictor of mortality?

BACKGROUND/OBJECTIVE: Mid-upper-arm circumference (MUAC) is a simple method of assessing nutritional status in children above 6 months of age. In 2007 World Health Organization (WHO) introduced a MUAC z-score for children above 3 months of age. We evaluated whether MUAC or MUAC z-score had the best ability to identify children with high short-term mortality risk in Guinea-Bissau. SUBJECTS/METHODS: The Bandim Health Project visits children 3-monthly until 3 years of age. MUAC is measured and deaths are registered. We studied a high-mortality cohort of children born in 1995-96 and a lower mortality cohort of children born in 2005-06. The prognostic ability of MUAC and MUAC z-score to predict mortality within 1 and 3 months after the MUAC assessment were compared by area under the receiver operating characteristic curve, sensitivity and positive predictive value. RESULTS: Compared with MUAC z-score, MUAC identified as malnourished more girls than boys (prevalence ratio (PR)=1.74 (1.52;2.01)) and more children aged 6-11 months than children aged 12-35 months (1.59 (1.38;1.82)). There was no difference in the prognostic ability of MUAC and MUAC z-score to predict mortality for children aged 6-35 months. The prognostic ability was higher when mortality was lower. MUAC performed well in the youngest infants. CONCLUSION: In the age group 6-35 months, MUAC and MUAC z-score had the same prognostic ability to predict short-term mortality. As MUAC is easier to use in field settings, there is no need to use MUAC z-score to identify children with a high-mortality risk.