By now, many women have received the COVID vaccine. I received my first Moderna dose in December and my second dose in January. The first time, I experienced some mild palpitations and chest discomfort. The second time, I had some moderate flu like side effects which lasted 36 hours and then thankfully resolved.

Why do women seem to react more to the vaccines than men?

The answer is our genes.

The X chromosome is full of immune response genes on our X chromosomes (we have 2) and something called escape X-inactivation. Estrogen and progesterone are also players of our immune response since almost every cell in our body has receptors for these hormones. These hormones actually regulate the immune cell function.

Also keep in mind, that more women tend to utilize the healthcare system and tend to report their side effects more.

It could also be that the men are keeping silent. :)