Assessing Willingness to receive COVID-19 Vaccines, associated factors and reasons for hesitancy among persons aged 13-80 years in Central Uganda. A population-based surveillance Cohort. (preprint)

Background: Vaccination is essential for controlling the COVID-19 pandemic. However adequate vaccine coverage is a critical to the effectiveness of the vaccine at a population level. Data on to acceptability of the vaccine in Urban areas are limited. This study examined the prevalence, factors associated with willingness to receive COVID-19 vaccine and reasons for hesitancy in the predominantly urban Wakiso district of Uganda. Methods: Data were obtained from a cross-sectional study conducted from March 1st, 2021, to September 30th, 2021 in the urban population-based cohort of the Africa Medical and behavioral Sciences Organization (AMBSO). Multivariable modified Poisson regression analysis was used to estimate adjusted prevalence ratios (aPR) and 95% confidence intervals of willingness to accept the COVID-19 vaccine. Results: A total of 1,903 participants were enrolled in the study; 61% of whom were females. About 63% of participants indicated willingness to accept the COVID-19 vaccine. Younger age groups (13-19 and 20-29) were less likely to accept the vaccine compared to the persons ages 40-49 years (aPR=0.79; 95% CI: 0.74, 0.84 for the 13-19 years and 0.93; 95% CI: 0.88, 0.98 for age group 20-29, compared to those ages 40-49 years. Post-primary education (aPR=1.05; 95% CI: 1.02, 1.09 compared to primary level), being a students and government staff (APR=1.13; 95% CI: 1.04, 1.23 compared to construction and Mechanic workers) were associated with willingness to receive COVID-19 vaccine. Some of the reported reasons for hesitancy included; concerns about side effects 154(57.0%), about 64(23.7%) did not think the vaccines were effective, and those who did not like the vaccines 32(11.9%). Conclusion: A substantial proportion of individuals were not willingness to receive the COVID-19 vaccine. More effort is needed to reduce vaccine hesitancy, especially among the young and people with lower formal education.

Severe Acute Respiratory Syndrome Coronavirus-2 Seropositivity in South-Central Uganda, During 2019 - 2021 (preprint)

Background: Globally, key subpopulations such as healthcare workers (HCWs) have a higher risk of contracting SARS-CoV-2. In Uganda, limited access to personal protective equipment amidst lack of clarity on the extent and pattern of the community disease burden may exacerbate this situation. We assessed SARS-CoV-2 antibody seroprevalence among high-risk sub-populations in South-central Uganda, including HCWs, persons within the general population previously reporting experiencing key COVID-19 like symptoms (fever, cough, loss of taste and smell) and archived plasma specimens collected between October 2019 – 18 th March 2020, prior to confirmation of COVID-19 in Uganda. Methods: : From November 2020 - January 2021, we collected venous blood from HCWs at selected health facilities in South-Central Uganda and from population-cohort participants who reported specific COVID-19 like symptoms in a prior phone-based survey conducted (between May to August 2020) during the first national lockdown. Pre-lockdown plasma collected (between October 2019 and March 18 th , 2020) from individuals considered high risk for SARS-CoV-2 infection was retrieved. Specimens were tested for antibodies to SARS-CoV-2 using the CoronaChek TM rapid COVID-19 IgM/IgG lateral flow test assay. IgM only positive samples were confirmed using a chemiluminescent microparticle immunoassay (CMIA) (Architect AdviseDx SARS-CoV-2 IgM) which targets the spike protein. SARS-CoV-2 exposure was defined as either confirmed IgM, both IgM and IgG or sole IgG positivity. Results: : The seroprevalence of antibodies to SARS-CoV-2 in HCWs was 21.1% [95%CI: 18.2-24.2]. Of the phone-based survey participants, 11.9% [95%CI: 8.0-16.8] had antibodies to SARS-CoV-2. Among 636 pre-lockdown plasma specimens, 1.7% [95%CI: 0.9-3.1] were reactive. Conclusions: : Findings suggest a high seroprevalence of antibodies to SARS-CoV-2 among HCWs and substantial exposure in persons presenting with specific COVID-19 like symptoms in the general population of South-central Uganda. Based on current limitations in serological test confirmation, it remains unclear whether pre-lockdown seropositivity implies prior SARS-CoV-2 exposure in Uganda.

Severe Acute Respiratory Syndrome Coronavirus-2 seropositivity in South-central Uganda, during 2019 - 2021 (preprint)

Globally, key subpopulations have a high risk of contracting SARS-CoV-2. In Uganda, limited access to personal protective equipment amidst lack of clarity on the extent of the community disease burden may exacerbate this situation. We assessed SARS-CoV-2 antibody seroprevalence among high-risk sub-populations, including healthcare workers, persons within the general population previously reporting experiencing key COVID-19 like symptoms and archived plasma specimens collected prior to confirmation of COVID-19 in Uganda. We collected venous blood from HCWs at selected health facilities and from population-cohort participants who reported specific COVID-19 like symptoms in a prior phone-based survey conducted during the first national lockdown (May-August 2020). Pre-lockdown plasma collected from individuals considered high risk for SARS-CoV-2 infection was retrieved. Specimens were tested for antibodies to SARS-CoV-2 using the CoronaChek rapid COVID-19 IgM/IgG lateral flow test assay. IgM only positive samples were confirmed using a chemiluminescent microparticle immunoassay (ARCHITECT AdviseDx SARS-CoV-2 IgM) which targets the spike. SARS-CoV-2 exposure was defined as either confirmed IgM, both IgM and IgG or sole IgG positivity. The seroprevalence of antibodies to SARS-CoV-2 in HCWs was 21.1% [95%CI: 18.2-24.2]. Of the phone-based survey participants, 11.9% [95%CI: 8.0-16.8] had antibodies to SARS-CoV-2. Among 636 pre-lockdown plasma specimens, 1.7% [95%CI: 0.9-3.1] were reactive. Findings suggest a high seroprevalence of antibodies to SARS-CoV-2 among HCWs and substantial exposure in persons presenting with specific COVID-19 like symptoms in the general population of South-central Uganda. Based on current limitations in serological test confirmation, it remains unclear whether pre-lockdown seropositivity implies prior SARS-CoV-2 exposure in Uganda.

Differential Performance of CoronaCHEK SARS-CoV-2 Lateral Flow Antibody Assay by Geographic Origin of Samples (preprint)

Background: We assessed the performance of CoronaCHEK lateral flow assay on samples from Uganda and Baltimore to determine the impact of geographic origin on assay performance. Methods: Serum samples from SARS-CoV-2 PCR+ individuals (Uganda: 78 samples from 78 individuals and Baltimore: 266 samples from 38 individuals) and from pre-pandemic individuals (Uganda 1077 and Baltimore 532) were evaluated. Prevalence ratios (PR) were calculated to identify factors associated with a false-positive test. Results: After first positive PCR in Ugandan samples the sensitivity was: 45% (95% CI 24,68) at 0-7 days; 79% (95%CI 64,91) 8-14 days; and 76% (95%CI 50,93) >15 days. In samples from Baltimore, sensitivity was: 39% (95% CI 30, 49) 0-7 days; 86% (95% CI 79,92) 8-14 days; and 100% (95% CI 89,100) 15 days post positive PCR. The specificity of 96.5% (95% CI 97.5,95.2) in Ugandan samples was significantly lower than samples from Baltimore 99.3% (95% CI 98.1,99.8), p<0.01. In Ugandan samples, individuals with a false positive result were more likely to be male (PR 2.04, 95% CI 1.03,3.69) or individuals who had a fever more than a month prior to sample acquisition (PR 2.87, 95% CI 1.12,7.35). Conclusions: Sensitivity of the CoronaCHEK was similar in samples from Uganda and Baltimore. The specificity was significantly lower in Ugandan samples than in Baltimore samples. False positive results in Ugandan samples appear to correlate with a recent history of a febrile illness, potentially indicative of a cross-reactive immune response in individuals from East Africa.