Previous COVID-19 infection may not protect you from suffering new infection

I am following the latest developments on COVID-19 and our efforts to control the pandemic or to deal with it as an endemic disease. I will update this page regularly, so if you are interested, check back often. As of June 25, 2022:

Vaccines Reduce COVID-19 Deaths: A study of the death records from 185 countries found that nearly two-thirds of the world’s population has had at least one COVID-19 vaccine, and it has prevented nearly 20 million deaths worldwide (The Lancet Infectious Diseases, June 23, 2022). More than 3.5 million COVID deaths have been reported since the first vaccines were administered in December 2020.

A Previous Infection May Not Protect You from Suffering a New Infection with the Most Recent Mutations of COVID-19: The COVID-19 virus keeps mutating to change its structure so that even if you are vaccinated with boosters and have had a previous infection, you may not be protected from being infected with a newly-mutated COVID-19 virus (Nature, June 17, 2022). The good news is that your partial protection from previous exposure to COVID-19 makes it more likely that if you are re-infected, you will have a mild case. The newest mutations called BA.1 – BA.5 are less likely to cause protracted COVID-19 infections, called long COVID, than the earlier viruses (Lancet, June 18, 2022).

Moderna’s New Vaccine: Moderna just released new study results showing a fivefold increase in neutralizing antibodies for its new booster that contains the original mRNA-1273 (Spikevax) vaccine and one specifically designed to target the more recent BA.4 and BA.5 Omicron subvariants that now account for more than 35 percent of U.S. cases.

How Your Immune System Works to Protect You: When you have an infection or are vaccinated against a certain virus, your immune system makes proteins called antibodies that attach to and kill the invading germs. However, after an infection or vaccination, the antibodies in your bloodstream drop to extremely low levels. You have immune memory T-cells that can remain and when you are exposed again to that virus, these memory T-cells recognize the invading germ by its surface proteins and cause your body to make new antibodies specifically against that invading germ, to help protect you from suffering a new infection.

Viruses Mutate: Viruses continuously mutate or change their surface proteins so that your immunen system may not recognize them and you can be infected again. The COVID-19 virus has already undergone many mutations. There was the Delta COVID-19 virus that mutated into the Omicron virus, so that people who had been infected with Delta were susceptible to being infected with Omicron within weeks of recovering from Delta. However, they were more likely to have at least partial immunity from their previous infection so that they had mild disease.

The COVID-19 Viruses Today: The most recent COVID-19 viruses in the United States came from the Omicron strain and are called BA.1 that has mutated to BA.2, to BA.3. to BA4 and now BA.5. Most of the most recent cases are now BA.4 and BA.5. A person who has been infected with BA.2 can still become infected later with BA.5 but is more likely to have a mild case. As of today we have no data to predict whether a person who has been infected with BA.2 will be protected from developing an infection with BA.5.

New Circulating Viruses Less Likely to Cause Long COVID: The Omicron mutations that are causing new infection today are half as likely to cause long COVID syndrome as the previous Delta strains. The new strains cause 4.4 percent of cases to suffer long COVID syndrome, which is well below the nearly 11 percent associated with the earlier Delta variant. However, the new variants are more contagious. Long COVID syndrome can include symptoms that last for weeks, months or years: fatigue, fever, malaise, trouble breathing, cough, chest pain, heart palpitations, dizziness, diarrhea, stomach pain, muscle ache, rash, irregular periods, foggy thinking, depression, anxiety, headaches, protracted sleep, and loss of smell and taste.

Dr. Gabe Mirkin is a Villager. Learn more at www.drmirkin.com