Safety of Tdap vaccine in pregnant women: an observational study

Petousis-Harris, Helen; Walls, Tony; Watson, Donna; Paynter, Janine; Graham, Patricia; Turner, Nikki

This was a prospective observational study conducted in two different geographical areas of NZ using the same outcome measures and database. There was some difference in recruitment and data collection methods. The Northern arm of the study was conducted primarily in Auckland and included other North Island centres. Auckland is a culturally diverse metropolitan city of 1.42 million in the North Island. Women being administered Tdap between 28 and 38 weeks gestation were identified by staff from 21 out of 24 participating general practices and the maternity clinics of three district health boards (DHBs) and referrals faxed to the study team from 30 January to 30 June 2014. The other arm was conducted in Canterbury, a more ethnically homogeneous South Island region of just over half a million. Recruitment for this arm began earlier, from late September 2012 to late June 2014. Participants aged 18-40 years and administered Tdap between 30 and 36 weeks gestation were identified via claims submitted by general practices (within 1 week of vaccination) for reimbursement from the local DHB for each vaccination service delivered.