Young female receives her second dose of the COVID-19 vaccine from a healthcare professional.

What Happens If You Skip the Second Dose of the COVID-19 Vaccine


Because the situation surrounding COVID-19 is constantly evolving, some information may not be up to date. Stay informed by following information from your local officials and by visiting the CDC website.

According to recent data from the CDC, 92% of people who received the first dose of the Pfizer-BioNTech or Moderna vaccine returned for their second  COVID-19 vaccine appointment within the recommended time frame. That still leaves about 8% of patients — or 5 million people — who have missed their second dose. 

Why is it a problem if people don’t get the second dose of the COVID-19 vaccine?

It is important to receive both doses of the Pfizer BioNTech and Moderna vaccines for someone to be considered fully vaccinated. The first dose is known as the priming dose, introducing the mRNA to the body. The second dose boosts that immune response so the body is ready to fight off the virus if it becomes exposed. The first dose provides about 50-60% protection against the novel coronavirus, which jumps up to 94% with the second dose.

Why are people not getting the second dose of the COVID-19 vaccine?

There are a number of potential factors contributing to people not returning for their second dose of the COVID-19 vaccine. One factor could be that people can’t get their work schedules to align with setting up and attending their second visits. There could also be some technical issues involved; with more pharmacies and vaccination sites opening, if a person received their vaccine doses at two different locations, the data may not have synced up in the reporting.

Others may be skipping their second dose because they are afraid of developing side effects, such as mild flu-like symptoms, fatigue, fever, and soreness in the injection arm - all of which are signs that the vaccine is working and your body is building an immune response. Lastly, some people may just feel like their first dose is sufficient to protect them from getting ill with COVID-19. 

What do I do if I missed my window for getting my second dose of the COVID-19 vaccine?

The window for receiving the second dose of the Pfizer BioNTech is three weeks, or 21 days, while the time frame is four weeks, or 28 days, for the Moderna vaccine. While this is the recommended time, the CDC says the second dose is effective up to six weeks, or 42 days, after receiving the first dose of the vaccine. 

These guidelines are based on the clinical trial studies performed to get the vaccine to emergency use authorization (EUA) approval. Physicians, including Baylor St. Luke’s Medical Group Area Medical Director Dr. Charles Sims, say that it’s not possible to determine whether delaying the second dose would impact the extent of the immune response. 

“Missing [your second dose appointment] is not the end of the world. You should get it when you can. Even if it is months later, it is still a booster. You may not get quite as much, but you’re still at 80% at worst.”

-Dr. Charles Sims, Medical Director for Infectious Disease in St. Luke’s Health’s North Houston Market and the Local Health Authority for Montgomery County

Baylor St. Luke’s has been designated as a vaccine hub by the State of Texas. Our vaccination sites are located on the campus of Texas Southern University. After receiving your first dose at one of our sites, more information will be provided about scheduling your second dose. Learn where you can get your COVID-19 vaccine with St. Luke’s Health today.

Sources:

ABC News | 2nd vaccine shot statistics show majority getting it, only 5 million missing it: CDC

Business Insider | The CDC says millions of Americans aren't receiving the 2nd dose of the coronavirus vaccine

USA Today | About 92% of Americans who got the COVID-19 vaccine returned for their second shot. That's good, but experts say the rest should do it now.

Health | What Happens If You Miss Your 2nd COVID-19 Shot? Here’s What to Do—And Why It’s So Important to Get Both Doses

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