Timing of vaccination during pregnancy
WHO recommends vaccination of pregnant women at any stage during pregnancy to protect both the mother and, through her, her young infant. This recommendation is supported by two considerations: vaccination at an early stage provides benefits to the pregnant woman, and immunization in the later trimesters of pregnancy maximizes protection to the newborn [32, 34-36]. The optimal timing for influenza vaccination for pregnant women is just before the influenza season starts, thus providing protection during the peak of the influenza season.
A single-dose injection is typically sufficient to provide protection against influenza virus infection in pregnant women for the period of the influenza season.
In practice, pregnant women may have limited access to influenza vaccination in low-resource settings. Only an estimated 54% of pregnant women attend at least four recommended antenatal visits, whereas an estimated 82% benefit from at least one antenatal visit [28]. This limits the opportunity to reach a large number of pregnant women with the vaccine prior to the influenza season. In areas of limited antenatal coverage, it may be preferable to recommend vaccination at the first (and possibly only) antenatal care visit or at another medical consultation during pregnancy with the formulation of the influenza vaccine available at the time of the year [32].