Influenza and Pregnancy: A Review of the Literature from India

Abstract

Maternal influenza infection is known to cause substantial morbidity and mortality among pregnant women and young children. Many professional healthcare bodies including the World Health Organization (WHO) have identified pregnant women as a priority risk group for receipt of inactivated seasonal influenza vaccination. However influenza prevention in this group is not yet a public health priority in India. This literature review was undertaken to examine the Indian studies of influenza among pregnant women. Eight Indian studies describing influenza burden and/or outcomes among pregnant women with influenza were identified. In most studies, influenza A (pH1N1) was associated with increased maternal mortality (25–75%), greater disease severity, and adverse fetal outcomes as compared to nonpregnant women. Surveillance for seasonal influenza infections along with higher quality prospective studies among pregnant women is needed to quantify disease burden, improve awareness among antenatal care providers, and formulate antenatal influenza vaccine policies.

Influenza Vaccine Requirements in Pregnant Women

“…Fetal malformations and other illnesses have been noted in cases of influenza in pregnancy [8]. Preterm delivery is an oft-recognized adverse outcome, as has been studied by Newsome et al in the USA [3]. This study showed that 63.6 % of pregnant women severely ill with influenza had preterm deliveries and 43.8 % had low birth weight babies as compared to the national averages.…”

“…The immunity shifts away from the cell-mediated immunity toward the humoral immunity [2]. There is a selective suppression of the T helper-type I cell-mediated immunity, with resultant impaired maternal response to infection [3]. Put together with the organ system alterations, the pregnant woman is at an increased risk of severe influenza.…”

“…Pregnant women tend to develop more severe complications due to their altered immune and physiological status [1,3].…”

“…During the previous influenza pandemics since 1918, 1957 and 2009, it was found that pregnant women were at high risk of developing complications [3]. Even during the interpandemic periods, pregnant women have been found to have an 18 times higher likelihood of hospitalization, especially if they contracted infection in the later stages of pregnancy.…”

“…Even during the interpandemic periods, pregnant women have been found to have an 18 times higher likelihood of hospitalization, especially if they contracted infection in the later stages of pregnancy. Associated comorbid conditions like diabetes or asthma, chronic cardiac or renal disease, and immunosuppressive disorders in pregnant women increase the likelihood of morbidity by at least 3-4 times more [2,3]. Obesity during pregnancy is also associated with higher morbidity [5].…”