HIV-1 and HIV-2 prevalence, risk factors and birth outcomes among pregnant women in Bissau, Guinea-Bissau: a retrospective cross-sectional hospital study

The human immunodeficiency virus (HIV) remains a leading cause of maternal morbidity and mortality in Sub-Saharan Africa. Prevention of mother-to-child transmission (PMTCT) has proven an effective strategy to end paediatric infections and ensure HIV-infected mothers access treatment. Based on cross-sectional data collected from June 2008 to May 2013, we assessed changes in HIV prevalence, risk factors for HIV, provision of PMTCT antiretroviral treatment (ART), and the association between HIV infection, birth outcomes and maternal characteristics at the Simão Mendes National Hospital, Guinea-Bissau’s largest maternity ward. Among 24,107 women, the HIV prevalence was 3.3% for HIV-1, 0.8% for HIV-2 and 0.9% for HIV-1/2. A significant decline in HIV-1, HIV-2, and HIV-1/2 prevalence was observed over time. HIV infection was associated with age and ethnicity. A total of 85% of HIV-infected women received ART as part of PMTCT, yet overall treatment coverage during labour and delivery declined significantly for both mothers and infants. Twenty-two percent of infants did not receive treatment, and 67% of HIV-2-infected mothers and 77% of their infants received ineffective non-nucleoside reverse transcriptase inhibitors for PMTCT. Maternal HIV was associated with low birth weight but not stillbirth. Inadequate continuity of care and ART coverage present challenges to optimal PMTCT in Guinea-Bissau

Long-term detection of SARS-CoV-2 antibodies after infection and risk of re-infection

OBJECTIVES: To evaluate long-term sensitivity for detection of total antibodies against SARS-CoV-2 METHODS: From week 41, 2020, through week 26, 2021, all Danish blood donations were tested for SARS-CoV-2 antibodies with the Wantai assay. The results were linked with polymerase chain reaction (PCR) test results from the Danish Microbiological Database (MiBa). RESULTS: During the study period, 105,646 non-vaccinated Danish blood donors were tested for SARS-CoV-2 antibodies, and 3,806 (3.6%) had a positive PCR test before the blood donation. Among the donors with a positive PCR test, 94.2% subsequently also had a positive antibody test. The time between the positive PCR test and the antibody test was up to 15 months and there was no evidence of a decline in proportion with detectable antibodies over time. A negative serological result test was associated with a higher incidence of re-infection (Incidence Rate Ratio = 0.102 (95% confidence interval (CI): 0.039–0.262)). CONCLUSION: Among healthy blood donors, 94.2% developed SARS-CoV-2 antibodies after infection, and a lack of detectable antibodies was associated with re-infection

Optimizing recovery of frozen human peripheral blood mononuclear cells for flow cytometry.

Live peripheral blood mononuclear cells (PBMCs) can be frozen and thawed for later analyses by adding and removing a cryoprotectant, such as dimethyl sulfoxide (DMSO). Laboratories across the world use various procedures, but published evidence of optimal thawing procedures is scarce.PBMCs were separated from blood collected from healthy Danish blood donors, and stored at -80°C after adding of DMSO. The essential steps in the thawing procedure were modified and performance was evaluated by flow cytometry with respect to the percentage and total yield of viable PMBCs.The best-performing washing medium was Roswell Park Memorial Institute (RPMI) 1640 at 37°C with 20% fetal bovine serum. When using 10 mL washing medium in a 15-mL Falcon tube, samples should be centrifuged for at least 10 minutes at 500 g. We failed to detect any differences between the tested methods of mixing PBMCs with washing medium. Likewise, neither the thawing duration nor centrifugation temperature (20°C and 37°C) had any effect. PBMCs could be incubated (rested) for up to eight hours in a 37°C 5% CO2 incubator without affecting cell counts, but incubating PBMCs for 16 hours significantly decreased viability and recovery. In general, high viability was not necessarily associated with high recovery.Changing the thawing procedure significantly impacted PBMC viability and live cell recovery. Evaluating both viability and live PBMC recovery are necessary to evaluate method performance. Investigation of differential loss of PBMC subtypes and phenotypic changes during thawing and incubation requires further evaluation

Impact of washing-medium temperature on viability (A) and PBMC recovery (B).

<p>20 donors included. Ref.: reference group. **: p<0.01.</p

PBMC viability (A) and absolute live PBMC recovery (B) by incubation.

<p>Samples were stored in a 37°C incubator with 5% CO₂. Paired samples from 20 donors were included. Ref.: reference group. NS: non-significant. *: p<0.05. **: p<0.01.</p