Advocacy, policies and practicalities of preventive chemotherapy campaigns for African children with schistosomiasis.

Preventive chemotherapy campaigns against schistosomiasis have progressively scaled-up during the last decade, administering single standard dose praziquantel (40 mg/kg) treatments to millions of African children. Steps taken in securing international advocacy and national level implementation are traced to highlight an international treatment platform set for further expansion, including surveillance of schistosomiasis, school-level targeting with better on-site drug administration and annual reporting of programmatic indicators (i.e., treatment coverage), potentially in real-time. Several shortcomings in need of resolution are identified and efficacy of praziquantel is assessed by a systematic review. If WHO predictions in reduction of schistosomiasis are to be realized, careful international harmonization and tailoring of national resources are required. Maintaining an effective drug distribution system and regularly checking drug efficacy are paramount

Prevalence (in %) and arithmetic and geometric means (in epg) of <i>S. mansoni</i> infection as determined by microscopy and rapid diagnostic test – Circulating Cathodic Antigen (CCA) - for all children (5 months–7 year olds) surveyed at baseline of the treatment efficacy study.

<p>Prevalence of infection did not significantly differ between the two treatment groups (treatment-naïve and previously treated) irrespective of diagnostic test employed.</p

Percentage of symptoms reported after treatment (left column) and percentage of symptoms ameliorated (right column).

<p>A side-effect is defined as a symptom absent before treatment and experienced after treatment; amelioration of a symptom is defined as a symptom that was experienced before treatment and no longer present 24 hours afterwards. A–B: children (N = 781) v. mothers (N = 539); C–D: baseline (N = 781) v. follow-ups (children only, N = 171 and 167, respectively for 6 and 12 month follow-ups); E–F: PZQ+ALB integrated chemotherapy (N = 529) v. ALB monotherapy (N = 370, children only).</p

Cure and egg reduction rates (CR and ERR, respectively) as determined by egg output, in % (and CI₉₅), for treatment with a single dose of praziquantel (40 mg/Kg) against intestinal schistosomiasis in very young children (5 months–7 year olds); (1) is ERR of arithmetic mean, and (2) is ERR of geometric mean.

*<p>Information on sex and age of the child not available for all children.</p

Multivariate logistic regression to ascertain variables associated with “cure” (i.e. to become egg-negative after treatment) in 282 children (5 months–7 year olds).

<p>Time in water categories: 0 = zero hours, 1 = <30 min, 2 = 30–60 min, 3 = 60–120 min, 4 = >120 min.</p>*<p>34.6 mg/Kg was the minimum dosage given in our survey population, while the maximum dosage was 45.1 mg/Kg.</p

SARS-CoV-2 antibodies and breakthrough infections in the Virus Watch cohort

A range of studies globally demonstrate that the effectiveness of SARS-CoV-2 vaccines wane over time, but the total effect of anti-S antibody levels on risk of SARS-CoV-2 infection and whether this varies by vaccine type is not well understood. Here we show that anti-S levels peak three to four weeks following the second dose of vaccine and the geometric mean of the samples is nine fold higher for BNT162b2 than ChAdOx1. Increasing anti-S levels are associated with a reduced risk of SARS-CoV-2 infection (Hazard Ratio 0.85; 95%CIs: 0.79-0.92). We do not find evidence that this antibody relationship with risk of infection varies by second dose vaccine type (BNT162b2 vs. ChAdOx1). In keeping with our anti-S antibody data, we find that people vaccinated with ChAdOx1 had 1.64 times the odds (95% confidence interval 1.45-1.85) of a breakthrough infection compared to BNT162b2. We anticipate our findings to be useful in the estimation of the protective effect of anti-S levels on risk of infection due to Delta. Our findings provide evidence about the relationship between antibody levels and protection for different vaccines and will support decisions on optimising the timing of booster vaccinations and identifying individuals who should be prioritised for booster vaccination, including those who are older, clinically extremely vulnerable, or received ChAdOx1 as their primary course. Our finding that risk of infection by anti-S level does not interact with vaccine type, but that individuals vaccinated with ChAdOx1 were at higher risk of infection, provides additional support for the use of using anti-S levels for estimating vaccine efficacy. [Abstract copyright: © 2022. The Author(s).

Differential Risk of SARS-CoV-2 Infection by Occupation: Evidence from the Virus Watch prospective cohort study in England and Wales

Abstract Background Workers across different occupations vary in their risk of SARS-CoV-2 infection, but the direct contribution of occupation to this relationship is unclear. This study aimed to investigate how infection risk differed across occupational groups in England and Wales up to April 2022, after adjustment for potential confounding and stratification by pandemic phase. Methods Data from 15,190 employed/self-employed participants in the Virus Watch prospective cohort study were used to generate risk ratios for virologically- or serologically-confirmed SARS-CoV-2 infection using robust Poisson regression, adjusting for socio-demographic and health-related factors and non-work public activities. We calculated attributable fractions (AF) amongst the exposed for belonging to each occupational group based on adjusted risk ratios (aRR). Results Increased risk was seen in nurses (aRR = 1.44, 1.25–1.65; AF = 30%, 20–39%), doctors (aRR = 1.33, 1.08–1.65; AF = 25%, 7–39%), carers (1.45, 1.19–1.76; AF = 31%, 16–43%), primary school teachers (aRR = 1.67, 1.42- 1.96; AF = 40%, 30–49%), secondary school teachers (aRR = 1.48, 1.26–1.72; AF = 32%, 21–42%), and teaching support occupations (aRR = 1.42, 1.23–1.64; AF = 29%, 18–39%) compared to office-based professional occupations. Differential risk was apparent in the earlier phases (Feb 2020—May 2021) and attenuated later (June—October 2021) for most groups, although teachers and teaching support workers demonstrated persistently elevated risk across waves. Conclusions Occupational differences in SARS-CoV-2 infection risk vary over time and are robust to adjustment for socio-demographic, health-related, and non-workplace activity-related potential confounders. Direct investigation into workplace factors underlying elevated risk and how these change over time is needed to inform occupational health interventions

Household overcrowding and risk of SARS-CoV-2: analysis of the Virus Watch prospective community cohort study in England and Wales.

Background: Household overcrowding is associated with increased risk of infectious diseases across contexts and countries. Limited data exist linking household overcrowding and risk of COVID-19. We used data collected from the Virus Watch cohort to examine the association between overcrowded households and SARS-CoV-2. Methods: The Virus Watch study is a household community cohort of acute respiratory infections in England and Wales. We calculated overcrowding using the measure of persons per room for each household. We considered two primary outcomes: PCR-confirmed positive SARS-CoV-2 antigen tests and laboratory-confirmed SARS-CoV-2 antibodies. We used mixed-effects logistic regression models that accounted for household structure to estimate the association between household overcrowding and SARS-CoV-2 infection. Results:26,367 participants were included in our analyses. The proportion of participants with a positive SARS-CoV-2 PCR result was highest in the overcrowded group (9.0%; 99/1,100) and lowest in the under-occupied group (4.2%; 980/23,196). In a mixed-effects logistic regression model, we found strong evidence of an increased odds of a positive PCR SARS-CoV-2 antigen result (odds ratio 2.45; 95% CI:1.43-4.19; p-value=0.001) and increased odds of a positive SARS-CoV-2 antibody result in individuals living in overcrowded houses (3.32; 95% CI:1.54-7.15; p-value. Conclusion:Public health interventions to prevent and stop the spread of SARS-CoV-2 should consider the risk of infection for people living in overcrowded households and pay greater attention to reducing household transmission