Back in March, officials from the FDA (Food and Drug Administration) decided which strains of influenza would make it into this year’s vaccine. This happens so early in order to allow pharmaceutical companies to actually create the vaccine in a secure and timely manner. Of course, nobody will know for certain which strains will dominate the flu season, so intelligent predictions need to be made based on data gathered by the World Health Organization (WHO).
The bottom line is that even if it is only September, the components of the flu shot are not going to change before the flu season strikes. What's more, your immunity won’t fade if you get it now instead of later, so why risk waiting longer?
If you’re a healthy person, you should get the flu shot. Period. However, there are a couple of exceptions, particularly for people who have a weakened immune system. According to the American Academy of Pediatrics (AAP), the "annual influenza vaccine is recommended for everyone 6 months and older” and that “vaccination remains the best available preventive measure to prevent influenza illness.” They also recommend that children should get the shot before the end of October, at the very latest.
Regardless of what stage of pregnancy a woman is in, including postpartum, there's absolutely no reason to skip this year's flu shot. It's perfectly safe for you and your baby, and will actually add an extra layer of protection, helping your pregnancy go as smoothly as possible.
Although most vaccines are still made in eggs, the latest research shows that the flu shot will not cause any issues for people who suffer from egg allergies. However, if you have an egg allergy, and are still afraid to take the shot, then you can use a vaccine made in other animal cells, which are entirely egg-free.
Seeing as the dominant strains of influenza vary periodically, the components of the flu shot will generally differ from one year to the next. In fact, the 2018/2019 version includes a strain of influenza B that has never been seen before. Relying on residual immunity from previous years is a risk we certainly wouldn't recommend taking.
Most kinds of flu shots are highly effective, however, there is a certain type that the AAP actively warns against. This is the live attenuated influenza vaccine, most commonly known as the influenza nasal spray. Evidence seems to suggest that live versions are less effective than inactivated ones, however, it should still be fine for people between the ages of 2 and 50. Anyone else should certainly opt for an inactivated version, which is the most common one available.