COVID-19 vaccination and transmission patterns among pregnant and postnatal women during the fifth wave of COVID-19 in a tertiary hospital in Hong Kong.

Introduction: Vaccination is a key strategy to control the coronavirus disease 2019 (COVID-19) pandemic. Safety concerns strongly influence vaccine hesitancy. Disease transmission during pregnancy could exacerbate risks of preterm birth and perinatal mortality. This study examined patterns of vaccination and transmission among pregnant and postnatal women during the fifth wave of COVID-19 in Hong Kong.

Methods: The Antenatal Record System and Clinical Management System of the Hospital Authority was used to retrieve information concerning the demographic characteristics, vaccination history, COVID-19 status, and obstetric outcomes of women who were booked for delivery at Queen Mary Hospital in Hong Kong and had attended the booking antenatal visit from 1 July 2021 to 30 June 2022.

Results: Among 2396 women in the cohort, 2006 (83.7%), 1843 (76.9%), and 831 (34.7%) had received the first, second, and third doses of COVID-19 vaccine, respectively. Among 1012 women who had received the second dose, 684 (67.6%) women were overdue for their third dose. There were 265 (11.1%) reported COVID-19 cases. Women aged 20 to 29 years had a low vaccination rate but the highest disease rate (19.1%). The disease rate was more than tenfold higher in women who had no (20.3%) or incomplete (18.8%) vaccination, compared with women who had complete vaccination (2.1%; P<0.001).

Conclusion: Acceptance of COVID-19 vaccination was low in pregnant women. Urgent measures are needed to promote vaccination among pregnant women before the next wave of COVID-19.