RESUMO
BackgroundThe populations antibody response is a key factor in comprehending SARS-CoV-2 epidemiology. This is especially important in African settings where COVID-19 impact, and vaccination rates are relatively low. This study aimed at characterizing the Immunoglobulin G (IgG) and Immunoglobulin M (IgM) in both SARS-CoV-2 asymptomatic and symptomatic individuals in Kisumu and Siaya counties in Western Kenya using enzyme linked immunosorbent assays. ResultsThe IgG and IgM overall seroprevalence in 98 symptomatic and asymptomatic individuals in western Kenya between December 2021-March 2022 was 76.5% (95% CI =66.9-84.5) and 31.6% (95% CI =22.6-41.8) respectively. In terms of gender, males had slightly higher IgG positivity 87.8% (36/41) than females 68.4% (39/57). Amidst the ongoing vaccination roll-out during the study period, over half of the study participants (55.1%, 95% CI= 44.7-65.2) had not received any vaccine. About one third, (30.6%, 95% CI= 21.7-40.7) of the study participants had been fully vaccinated, with close to a quarter (14.3% 95% CI=8.04-22.8) partially vaccinated. When considering the vaccination status and seroprevalence, out of the 30 fully vaccinated individuals, IgG seropositivity was 86.7% (95% CI =69.3-96.2) and IgM seropositivity was 40% (95% CI =22.7-59.4). Out of the participants that had not been vaccinated at all, IgG seroprevalence was 70.3% (95% CI 56.4-82.0) with 20.4% (95% CI 10.6-33.5) seropositivity of IgM antibodies. SARs-CoV-2 PCR positivity did not significantly predict IgG (p = 0.457 [95% CI 0.514-4.371]) and IgM (p = 0.858 [95% CI 0.350-2.395]) positivity. ConclusionOur data indicate a high seroprevalence of antibodies to SARS-CoV-2 in western Kenya. This suggests larger fraction of the population were infected with SARS-CoV-2 within the defined period than what PCR testing could cover.
RESUMO
BACKGROUND@#Influenza A viruses pose a significant risk to human health because of their wide host range and ability to reassort into novel viruses that can cause serious disease and pandemics. Since transmission of these viruses between humans and pigs can be associated with occupational and environmental exposures, we investigated the association between occupational exposure to pigs, occurrence of acute respiratory illness (ARI), and influenza A virus infection.@*METHODS@#The study was conducted in Kiambu County, the county with the highest level of intensive small-scale pig farming in Kenya. Up to 3 participants (> 2 years old) per household from pig-keeping and non-pig-keeping households were randomly recruited and followed up in 2013 (Sept-Dec) and 2014 (Apr-Aug). Oropharyngeal (OP) and nasopharyngeal (NP) swabs were collected from participants with ARI at the time of study visit. For the animal study, nasal and oropharyngeal swabs, and serum samples were collected from pigs and poultry present in enrolled households. The human and animal swab samples were tested for viral nucleic acid by RT-PCR and sera by ELISA for antibodies. A Poisson generalized linear mixed-effects model was developed to assess the association between pig exposure and occurrence of ARI.@*RESULTS@#Of 1137 human participants enrolled, 625 (55%) completed follow-up visits including 172 (27.5%) pig workers and 453 (72.5%) non-pig workers. Of 130 human NP/OP swabs tested, four (3.1%) were positive for influenza A virus, one pig worker, and three among non-pig workers. Whereas none of the 4462 swabs collected from pig and poultry tested positive for influenza A virus by RT-PCR, 265 of 4273 (6.2%) of the sera tested positive for virus antibodies by ELISA, including 11.6% (230/1990) of the pigs and 1.5% (35/2,283) of poultry. The cumulative incidence of ARI was 16.9% among pig workers and 26.9% among the non-pig workers. The adjusted risk ratio for the association between being a pig worker and experiencing an episode of ARI was 0.56 (95% CI [0.33, 0.93]), after adjusting for potential confounders.@*CONCLUSIONS@#Our findings demonstrate moderate seropositivity for influenza A virus among pigs, suggesting the circulation of swine influenza virus and a potential for interspecies transmission.
