The Avon Longitudinal Study of Parents and Children - a resource for COVID-19 research: questionnaire data capture July 2021 to December 2021, with a focus on long COVID

ALSPAC, the Avon Longitudinal Study of Parents and Children is a prospective population-based cohort study. Pregnant women were recruited in 1990-1992 and the study has followed them, their partners (Generation 0; G0) and their offspring (Generation 1; G1) for over 30 years. During the coronavirus 2019 (COVID-19) pandemic, ALSPAC deployed a series of online questionnaires to capture participant experiences during this unprecedented time. In July 2021, a fifth questionnaire was deployed which primarily focussed on the symptoms of long COVID, also known as post-COVID syndrome. G0 and G1 participants were offered both online and paper questionnaires between 21 st July 2021 and 11 th December 2021. Of 21,138 invitations, 11,148 (52.8%) participants returned the questionnaire (4,763 original mothers [mean age 59.1 years], 2,074 original fathers/partners [mean age 62.0 years] and 4,311 offspring [mean age 29.0 years]). Of these 11,148 participants, 2835 (25.4%) had not completed any of the previous COVID-19 questionnaires, while 3480 (31.2%) had returned all four previous questionnaires. In this questionnaire, 1077 participants (9.8%) reported a previous positive COVID-19 test over the course of the pandemic. Of these, 109 (1.0%) had received medical advice that they likely had COVID-19, and 838 (7.6%) suspected that they had had COVID-19. Almost a third of participants (n=796, 31.1%) reported possible long COVID (experiencing symptoms for at least 4 weeks), whilst 351 (13.7%) reported symptom duration of 12 weeks or more (post-COVID syndrome). G0 mothers were more likely to report a longer duration of symptoms compared to their partners and their children. The fifth COVID-19 questionnaire deployed by ALSPAC and the data obtained from are described in this data note.