ABSTRACT
Background: A common complication of any respiratory disease by a virus could be a secondary bacterial infection, which is known to cause an increase in severity. It is, however, not clear whether the presence of some opportunistic pathogens called pathobionts contributes to the severity of the disease. In COVID-19 patients, undetected bacterial co-infections may be associated with the severity of the disease. Therefore, we investigated the implications of bacterial co-infections in COVID-19 cases. Results: This is a cross-sectional study that involved archived specimens collected from nasopharyngeal samples of 150 people for COVID-19 screening in Lagos. DNA extraction from the samples was carried out to determine the presence of five respiratory bacterial pathogens using nested real-time PCR, and data were analysed using the Chi-square test. Of the 150 samples collected, 121 (80.7%) were positive for SARs-CoV-2 infection and 29 were negative. The proportion of patients with bacteria co-infection in COVID-19-negative, asymptomatic, and mild cases were 93.1%, 70.7%, and 67.5%, respectively. There was no statistically significant difference between mild COVID-19 conditions and bacteria co-infection (p = 0.097). There was also no significant difference in the nasal carriage of Staphylococcus aureus, Mycoplasma pneumoniae, and Haemophilus spp. However, there was a statistically significant increase in the carriage of Moraxella catarrhalis and Chlamydophila pneumoniae among COVID-19-negative patients when compared with the positive patients (p value = 0.003 and 0.000 for Moraxella catarrhalis and Chlamydophila pneumoniae, respectively). Conclusions: The current study shows that bacterial co-infection and superinfection with COVID-19 are not associated with mild and asymptomatic COVID-19 cases in our setting. However, given the high prevalence of Staphylococcus aureus and Mycoplasma pneumoniae among the mild COVID-19 cases seen in this study, early diagnosis and treatment of these bacterial co-infections are still encouraged to mitigate the effect on the severity of COVID-19.
ABSTRACT
Real-world data on vaccine-elicited neutralising antibody responses for two-dose AZD1222 in African populations are limited. We assessed baseline SARS-CoV-2 seroprevalence and levels of protective neutralizing antibodies prior to vaccination rollout using binding antibodies analysis coupled with pseudotyped virus neutralisation assays in two cohorts from West Africa: Nigerian healthcare workers (n = 140) and a Ghanaian community cohort (n = 527) pre and post vaccination. We found 44 and 28% of pre-vaccination participants showed IgG anti-N positivity, increasing to 59 and 39% respectively with anti-receptor binding domain (RBD) IgG-specific antibodies. Previous IgG anti-N positivity significantly increased post two-dose neutralizing antibody titres in both populations. Serological evidence of breakthrough infection was observed in 8/49 (16%). Neutralising antibodies were observed to wane in both populations, especially in anti-N negative participants with an observed waning rate of 20% highlighting the need for a combination of additional markers to characterise previous infection. We conclude that AZD1222 is immunogenic in two independent West African cohorts with high background seroprevalence and incidence of breakthrough infection in 2021. Waning titres post second dose indicates the need for booster dosing after AZD1222 in the African setting despite hybrid immunity from previous infection.