An investigation of the utilisation and safety of influenza A(H1N1)pdm 2009 vaccines using the UK GPRD

• Main Author: Sammon, Cormac James
• Published: University of Bath 2013
• Subjects: 615.372
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.616574

Background Following the outbreak of the Influenza A(H1Nl) pandemic, mass vaccination was recommended in the UK, Europe and many other countries throughout the world. Given the limited pre-marketing experience with these vaccines, national and international post-marketing surveillance was recommended. Aim To contribute to the post-marketing surveillance of the influenza A(H1Nl) pdm09 vaccine using the GPRD, to assess the performance of the GPRD as a vaccine surveillance tool and to assess the potential of the VAESCO collaborative working model. Methods Several studies were carried out, both independently using UK GPRD data and in collaboration with VAESCO partners elsewhere in Europe. Cohort, case-control and self-controlled case series methodologies were used to estimate influenza A(H1Nl) pdm09 vaccine uptake in high risk groups, provide background rates of events commonly reported following vaccination for use in passive surveillance and evaluate the risk of Guillain-Barre syndrome and foetal death following influenza A(H1Nl) pdm09 vaccination. Results Uptake of influenza A(H1Nl) pdm09 vaccine in clinical risk groups (40.3%) and pregnant women (21.6%) was low. Background rates of facial nerve palsy varied by data source, age, calendar year and calendar month. The risk of Guillain-Barre syndrome was not significantly higher among vaccinated than unvaccinated individuals in the case control (ORadj 1.0, cr9S 0.3 to 2.7) or self-controlled case series (IRRadj 1.3 CIgs 0.6 to 2.7) studies while the risk of first (HRunadj 0.74, CIgs 0.62 to 0.88), second (HRunadj 0.59, CIgs 0.45 to 0.77) and third (HRunadj 0.70, CIgs 0.47 to 1.03) trimester foetal death was not higher in vaccinated than unvaccinated individuals.