Zika virus infection during pregnancy and vertical transmission: case reports and peptide-specific cell-mediated immune responses.

Zika virus (ZIKV) infection in pregnant women is associated with birth defects, which are more prevalent and severe the earlier in pregnancy the infection occurs. Pregnant women at risk of possible ZIKV exposure (n = 154) were screened using ELISA for ZIKV IgM and IgG. Nine of 154 (5.84%) pregnant women who underwent screening exhibited positive ZIKV serology. Of these, two maternal infections were confirmed by real-time RT-PCR and five were considered probable, but only three of those were retained for further analysis based on strict diagnostic criteria. Plaque reduction neutralization tests (PRNT) confirmed ZIKV infection in nine cases (5.84%). Two cases of vertical ZIKV transmission were confirmed by PCR. One infant showed no signs of congenital ZIKV syndrome and had a normal developmental profile despite first-trimester maternal infection. In the second case, pregnancy was terminated. Production of interferon γ (IFN-γ) by peripheral blood mononuclear cells obtained from pregnant women and umbilical cord blood was measured using enzyme-linked immunospot assay (ELISpot) after stimulation with panels of synthetic peptides derived from the sequence of ZIKV proteins. This analysis revealed that, among all peptide pools tested, those derived from the ZIKV envelope protein generated the strongest IFN-γ response.

Challenges to achieving and maintaining viral suppression among children living with HIV.

OBJECTIVES: The objective of this study was to determine the time to, and durability of, viral suppression, among Canadian children living with HIV after initiation of combination antiretroviral therapy (cART). DESIGN: Prospective, multicenter Canadian cohort study (Early Pediatric Initiation Canada Child Cure Cohort), using both prospective and retrospectively collected data. METHODS: Kaplan-Meir survival estimates with Cox regression were used to determine the time to and risk factors for viral suppression, defined as two consecutive undetectable viral loads (<50 copies/ml) at least 30 days apart after initiation of cART. RESULTS: A total of 228 children were enrolled between December 2014 and December 2018. The time to viral suppression was significantly shorter among children initiating cART after 5 ≤ 5 vs. years or less of age [adjusted hazard ratio (aHR) 1.57, 95% confidence interval (CI) 1.13-2.20], among those born after 2010 vs. prior (aHR 1.71, 95% CI 1.04-2.79), and among those without child protection services involvement (aHR 1.44, 95% CI 1.03-2.01). Overall, 27% of children had a viral rebound within 3 years of achieving viral suppression; the risk of viral rebound was significantly lower among children initiating cART after 5 vs. 5 years or less of age [adjusted odds ratio (aOR): 0.32, 95% CI 0.13-0.81], those whose families had not received social assistance (aOR 0.16, 95% CI 0.06-0.46), and females vs. males (aOR 0.51, 95% CI 0.26-0.99). CONCLUSION: Only 73% of the children in the Early Pediatric Initiation Canada Child Cure Cohort had maintained viral suppression 3 years after it was first achieved. Age at cART initiation, and socioeconomic factors were predictors of both time to viral suppression and risk of viral rebound in this cohort.