ABSTRACT
Objectives We assessed the prevalence of immunoglobulin G (IgG) and immunoglobulin M (IgM) against four endemic human coronaviruses (HCoVs) and two SARS-CoV-2 antigens, among vaccinated and unvaccinated staff at health care centres in Uganda, Sierra Leone, and the Democratic Republic of Congo (DRC). Methods Government health facility staff who had patient contact in Goma (DRC), Kambia District (Sierra Leone), and Masaka District (Uganda) were enrolled. Questionnaires and blood samples were collected at three timepoints over four months. Blood samples were analysed with the Luminex MAGPIX. Results Among unvaccinated participants, the prevalence of IgG/IgM antibodies against SARS-CoV-2 RBD or N-protein at enrolment was 70% in Goma (138/196), 89% in Kambia (112/126) and 89% in Masaka (190/213). IgG responses against endemic HCoVs at baseline were not associated with SAR-CoV-2 sero-acquisition during follow-up. Among vaccinated participants, those who had evidence of SARS-CoV-2 IgG/IgM at baseline tended to have higher IgG responses to vaccination compared to those SARS-CoV-2 seronegative at baseline, controlling for the time of sample collection since vaccination. Conclusions The high levels of natural immunity and hybrid immunity should be incorporated into both vaccination policy and prediction models of the impact of subsequent waves of infection in these settings.
Subject(s)
Hemorrhagic Fever, Crimean , Severe Acute Respiratory SyndromeABSTRACT
Introduction This study aimed to determine whether the COVID-19 pandemic had an impact on the number of people seen at public facilities in Uganda, the Democratic Republic of the Congo (DRC) and Sierra Leone for essential primary healthcare services. Methods The number of weekly consultations for antenatal care (ANC), outpatient (OPD), expanded programme on immunisations (EPI), family planning (FP) services and HIV, for the period of January 2018-December 2020, were collected from 25 primary healthcare facilities in Masaka district, Uganda, 21 health centres in Goma, DRC, and 29 facilities in Kambia district, Sierra Leone. Negative binomial regression models accounting for facility level clustering and season were used to analyse changes in activity levels between 2018, 2019 and 2020. Results We found no evidence that the COVID-19 pandemic affected the number of OPD, EPI or ANC consultations in Goma. Family planning consultations were 17% lower in March-July 2020 compared to 2019, but this recovered by December 2020. New diagnoses of HIV were 34% lower throughout 2020 compared to 2019. Compared to the same periods in 2019, facilities in Sierra Leone had 18-29% fewer OPD consultations throughout 2020, and 27% fewer DTP3 doses in March-July 2020, but this had recovered by Jul-Dec. There was no evidence of differences in other services. In Uganda there were 20-35% fewer under-5 OPD consultations, 21-66% fewer MCV1 doses, and 48-51% fewer new diagnoses of HIV, throughout 2020, compared to 2019. There was no difference in the number of HPV doses delivered in 2020 compared to 2019. Conclusions The level of disruption appeared to correlate with the strength of lockdown measures in the different settings and community attitudes towards the risk posed by COVID-19. Mitigation strategies such as health communications campaigns and outreach services proved important to limit the impact of lockdowns on primary healthcare services.
Subject(s)
COVID-19 , HIV InfectionsABSTRACT
IntroductionThe high proportion of SARS-CoV-2 infections that have remained undetected presents a challenge to tracking the progress of the pandemic and estimating the extent of population immunity. MethodsWe used residual blood samples from women attending antenatal care services at three hospitals in Kenya between August 2020 and October 2021and a validated IgG ELISA for SARS-Cov-2 spike protein and adjusted the results for assay sensitivity and specificity. We fitted a two-component mixture model as an alternative to the threshold analysis to estimate of the proportion of individuals with past SARS-CoV-2 infection. ResultsWe estimated seroprevalence in 2,981 women; 706 in Nairobi, 567 in Busia and 1,708 in Kilifi. By October 2021, 13% of participants were vaccinated (at least one dose) in Nairobi, 2% in Busia. Adjusted seroprevalence rose in all sites; from 50% (95%CI 42-58) in August 2020, to 85% (95%CI 78-92) in October 2021 in Nairobi; from 31% (95%CI 25-37) in May 2021 to 71% (95%CI 64-77) in October 2021 in Busia; and from 1% (95% CI 0-3) in September 2020 to 63% (95% CI 56-69) in October 2021 in Kilifi. Mixture modelling, suggests adjusted cross-sectional prevalence estimates are underestimates; seroprevalence in October 2021 could be 74% in Busia and 72% in Kilifi. ConclusionsThere has been substantial, unobserved transmission of SARS-CoV-2 in Nairobi, Busia and Kilifi Counties. Due to the length of time since the beginning of the pandemic, repeated cross-sectional surveys are now difficult to interpret without the use of models to account for antibody waning.
Subject(s)
COVID-19 , Severe Acute Respiratory SyndromeABSTRACT
The high proportion of asymptomatic and undetected SARS-CoV-2 infections presents a challenge to tracking the progress of the pandemic and implementing control measures in Kenya. We determined the prevalence of IgG to SARS-CoV-2 in residual blood samples from mothers attending antenatal care services at 2 referral hospitals in Kenya. A total of 196 samples were analysed from Kenyatta National Hospital in Nairobi in August 2020, seroprevalence, adjusted for assay sensitivity and specificity, was 49.8% (95% CI 42.0-57.8). In Kilifi County Hospital in coastal Kenya, 419 samples were analysed between September and November 2020, seroprevalence, adjusted for assay sensitivity and specificity, increased from 1.3% (95% CI 0.03-4.8) in September to 10.9% (95% CI 6.1, 16.8) in November 2020. There has been substantial, unobserved transmission of SARS-CoV-2 in parts of Nairobi and Kilifi Counties.