Influenza vaccine: A viable option to protect pregnant women and infants from seasonal flu: A retrospective hospital‐based study in India

BACKGROUND: Influenza is a highly contagious disease with global annual outbreaks of 3-5 million severe cases and 0.25-0.5 million deaths. The risk is greater in pregnant women that results in high morbidity and mortality. OBJECTIVE: The objective of this study was to see the efficacy of influenza vaccine on pregnant women and their newborn upto 6 months. METHOD: This was a retrospective study (January 2016-March 2018). Records of 346 pregnant women were included in this study (vaccinated: 288; unvaccinated: 58). Women and infants were categorised into Category A, B or C according to the guidelines issued by the Ministry of Health and Family Welfare, India on influenza. RESULTS: The groups were comparable with respect to baseline characteristics. Greater number of women received influenza vaccine during the first trimester (n = 117). During the gestation period, majority of the women in the vaccinated group were symptom-free compared with the unvaccinated (92% vs 70.7%). Also, none of the vaccinated women were categorised into category C compared with one who was laboratory tested positive for influenza in the unvaccinated group. Similar results were seen postpartum and more number of infants remained symptom-free in the vaccinated group compared with unvaccinated (69.3% vs 25.9%). More number of infants were born pre-term in the unvaccinated group compared with vaccinated (15.5% vs 8.6%). CONCLUSIONS: Immunisation with influenza vaccine in any trimester during pregnancy was found to protect the mother and infants upto 6 months of age against seasonal influenza without significant maternal adverse effects. In order to improve vaccination rates, there must be a national vaccination policy and incorporation of maternal immunisation in standard antenatal care.