According to the new indications given by the Ministry of Health, the influenza vaccine can be administered at any stage of pregnancy before flu season starts (generally from late October to before Christmas). Keep in mind that approximately 2-3 weeks are needed before achieving an antibody response and this response must be complete before flu season peaks (generally late January-early February). The protection lasts throughout the season and you must get the influenza vaccine again with each new season because the virus changes every year.
Note: The influenza vaccine does not protect against Covid-19.
