I don’t want anyone to get Covid after being fully vaccinated, a so-called “breakthrough infection.” I wish they would never happen. The reality is, however, breakthrough infections do happen. And, it seems, they are happening more often this Fall.

This is not totally surprising. While it would be ideal for a vaccine to prevent infection – i.e., catching the virus at all – at the very least, a good vaccine will prevent you from getting very sick from the disease. On this latter front, the vaccines continue to hold up well.

Yet, if it were to happen – if someone were to get a breakthrough infection – research shows that this person ends up with very robust immunity.

Researchers from the Oregon Health & Science University studied 26 people who were fully vaccinated against SARS CoV-2 and subsequently got COVID and compared them with 26 people who were vaccinated but did not get COVID. They found the immunity after a breakthrough infection was substantial:

In fact, the immunity after a breakthrough infection helped protect against multiple variants of SARS CoV-2, including Delta (the study was conducted before Omicron was born):

This is also not surprising, as an infection after vaccination serves as a “booster shot,” of sorts, and it therefore greatly enhances one’s immunity.

Now, of course, this is not the best way to boost your immunity against COVID if you are vaccinated. Sometimes, even mild COVID infections can have lasting long-term effects.

The best way, in fact, to boost your immunity against COVID is to get a booster shot. In the United States, everyone over the age of 16 is eligible to get a booster shot 2 months after the J&J vaccine and 6 months after the mRNA vaccines. They are safe. They are effective. And they boost your immunity to a great degree.

Again, I do not wish a breakthrough infection on anyone. This disease is horrible, and I have seen its horror up close. If one does get a breakthrough, though, the silver lining is that the immunity after such infection is very, very robust.

Reference: Bates TA, McBride SK, Winders B, et al. Antibody Response and Variant Cross-Neutralization After SARS-CoV-2 Breakthrough Infection. JAMA. Published online December 16, 2021. doi:10.1001/jama.2021.22898