Mucosal immunity to poliovirus in children 0-15 years of age: A community-based study in Karachi, Pakistan in 2019.

This study assesses poliovirus type 1 (PV1) immunity in children to inform the contribution of mucosal immunity in and preventing poliovirus circulation. A community-based study was conducted in peri-urban Karachi, Pakistan. Randomly selected children (0-15 years) received oral poliovirus vaccine (OPV) challenge dose. Blood and stool samples were collected at several time points and evaluated for polio-neutralizing antibodies and serotype-specific poliovirus, respectively. 81/589 (14%) children excreted PV1 7 days post-OPV-challenge; 70/81 (86%) were seropositive at baseline. 12/610 (2%) were asymptomatic Wild Poliovirus Type 1 (WPV1) excretors. Most poliovirus excretors had humoral immunity, suggesting mucosal immunity in these children likely waned or never developed. Without mucosal immunity, they are susceptible to poliovirus infection, shedding, and transmission. Asymptomatic WPV1 excretion suggests undetected poliovirus circulation within the community.

Two-Year Duration of Immunity of Inactivated Poliovirus Vaccine: A Follow-up Study in Pakistan in 2020.

This was a follow-up study conducted in 2020 assessing changes in levels of type 2 poliovirus-neutralizing antibodies 2 years postimmunization in children who received inactivated poliovirus vaccine (IPV) in Karachi, Pakistan. Unexpectedly, the findings revealed an increase in seroprevalence of type 2 antibodies from 73.1% to 81.6% 1 year and 2 years after IPV, respectively. The increase in type 2 immunity could result from the intensive transmission of circulating vaccine-derived poliovirus type 2 (cVDPV2) in Karachi during the second year of IPV administration. This study suggests that the cVDPV2 outbreak detected in Pakistan infected large proportions of children in Karachi. Clinical Trials Registration . NCT03286803.

Impact of COVID-19 on feto-maternal and neonatal health in Karachi, Pakistan, A retrospective cohort study.

Scientific literature suggests that pregnant women are at greater risk of acquiring a more severe form of COVID-19 exposing both mother and child to a higher risk of obstetric and neonatal complications. These include increased hospitalization rates, ICU admissions, or ventilatory support among pregnant women when compared to COVID-19 negative pregnant womenA case-control study was conducted at the Aga Khan University Hospital, Karachi, Pakistan with the objective of evaluating the clinical presentation of COVID-19 in pregnancy and its effect on maternal and neonatal outcomes. Data was retrospectively collected from April 2020 till January 2022 of obstetric patients with COVID-19 positive cases and were compared with COVID-19 negative cases from the same time. A total of 491 women were included in the study, 244 cases and 247 controls. The most common complication amongst cases was gestational diabetes mellitus (n = 59, 24%), followed by gestational hypertension (n = 16, 31.7%), pre-eclampsia (n = 13, 5%) Pre-rupture of membrane (85.7%). Amongst the COVID positive mothers the most common presenting complaints were fever followed by dry cough, headache, and shortness of breath. It was observed that COVID-19 did not result in increased adverse maternal or neonatal outcomes compared to COVID-19 negative mothers.