Positivity rate, trend and associated risk factors of mother-to-child transmission of HIV among HIV-exposed infants.

BACKGROUND: Mother-To-Child-Transmission (MTCT) of Human Immunodeficiency Virus (HIV) occurs during pregnancy, delivery and breastfeeding, and cause infection among several new-borns. However, there is limited recent evidence on the burden of MTCT of HIV in Ethiopia from a large-scale data. Thus, this study aimed to determine the positivity rate, trend and associated risk factors of MTCT among HIV-exposed infants. METHODOLOGY: A cross-sectional study was conducted among 5,679 infants whose specimen referred to Ethiopian Public Health Institute HIV referral laboratory for Early Infant Diagnosis (EID) from January 01, 2016, to December 31, 2020. Data were extracted from the national EID database. Frequencies and percentages were used to summarize the data on characteristics of infants. Logistic regression analysis was employed to identify factors associated with positivity rate of MTCT of HIV. Level of significance was set at 5%. RESULTS: The mean age of the infants was 12.6 (± 14.6) weeks with an age range of 4 to 72 weeks. Half of the infants (51.4%) were female. The positivity rate of MTCT decreased from 2.9% in 2016 to 0.9% in 2020 with five-year average positivity rate of 2.6%. HIV test after six weeks (Adjusted odds ratio (AOR) = 2.7; 95% confidence interval (CI): (1.8-4.0,)); p < 0.001), absence of prevention of mother-to-child-transmission (PMTCT) service (AOR = 4.6; 95% CI: (2.9-7.4)); p = 0.001), nevirapine prophylaxis not received (AOR = 2.0; 95% CI: (1.3-3.2)); p < 0.001), and unknown ART status of the mother at delivery (AOR = 11; 95% CI: (5.5-22.1)); p < 0.001) were significantly associated with MTCT of HIV. CONCLUSION: The positivity rate of MTCT of HIV was showing declining tendency gradually in the study period. Strengthening PMTCT service, early HIV screening and starting ART for pregnant women, and early infant diagnosis are required to reduce the burden of HIV infection among infants exposed to HIV.

Effect of heat inactivation and bulk lysis on real-time reverse transcription PCR detection of the SARS-COV-2: an experimental study.

OBJECTIVE: This study aimed to investigate the effect of heat inactivation and chemical bulklysis on SARS-CoV-2 detection. RESULTS: About 6.2% (5/80) of samples were changed to negative results in heat inactivation at 60 °C and about 8.7% (7/80) of samples were changed to negative in heat inactivation at 100 °C. The Ct values of heat-inactivated samples (at 60 °C, at 100 °C, and bulk lysis) were significantly different from the temperature at 56 °C. The effect of heat on Ct value should be considered when interpreting diagnostic PCR results from clinical samples which could have an initial low virus concentration. The efficacy of heat-inactivation varies greatly depending on temperature and duration. Local validation of heat-inactivation and its effects is therefore essential for molecular testing.

Longitudinal profile of antibody response to SARS-CoV-2 in patients with COVID-19 in a setting from Sub-Saharan Africa: A prospective longitudinal study.

BACKGROUND: Serological testing for SARS-CoV-2 plays an important role for epidemiological studies, in aiding the diagnosis of COVID-19, and assess vaccine responses. Little is known on dynamics of SARS-CoV-2 serology in African settings. Here, we aimed to characterize the longitudinal antibody response profile to SARS-CoV-2 in Ethiopia. METHODS: In this prospective study, a total of 102 PCR-confirmed COVID-19 patients were enrolled. We obtained 802 plasma samples collected serially. SARS-CoV-2 antibodies were determined using four lateral flow immune-assays (LFIAs), and an electrochemiluminescent immunoassay. We determined longitudinal antibody response to SARS-CoV-2 as well as seroconversion dynamics. RESULTS: Serological positivity rate ranged between 12%-91%, depending on timing after symptom onset. There was no difference in positivity rate between severe and non-severe COVID-19 cases. The specificity ranged between 90%-97%. Agreement between different assays ranged between 84%-92%. The estimated positive predictive value (PPV) for IgM or IgG in a scenario with seroprevalence at 5% varies from 33% to 58%. Nonetheless, when the population seroprevalence increases to 25% and 50%, there is a corresponding increases in the estimated PPVs. The estimated negative-predictive value (NPV) in a low seroprevalence scenario (5%) is high (>99%). However, the estimated NPV in a high seroprevalence scenario (50%) for IgM or IgG is reduced significantly to 80% to 85%. Overall, 28/102 (27.5%) seroconverted by one or more assays tested, within a median time of 11 (IQR: 9-15) days post symptom onset. The median seroconversion time among symptomatic cases tended to be shorter when compared to asymptomatic patients [9 (IQR: 6-11) vs. 15 (IQR: 13-21) days; p = 0.002]. Overall, seroconversion reached 100% 5.5 weeks after the onset of symptoms. Notably, of the remaining 74 COVID-19 patients included in the cohort, 64 (62.8%) were positive for antibody at the time of enrollment, and 10 (9.8%) patients failed to mount a detectable antibody response by any of the assays tested during follow-up. CONCLUSIONS: Longitudinal assessment of antibody response in African COVID-19 patients revealed heterogeneous responses. This underscores the need for a comprehensive evaluation of seroassays before implementation. Factors associated with failure to seroconvert needs further research.