Nearly one year ago, the first COVID-19 vaccine was administered in the United States. Now, with more than 400 million COVID-19 shots given to American citizens, U.S. health regulators are discussing whether people need to get a booster shot or a third dose to help them maintain their immunity against the virus.
But how do you tell the difference between a booster shot and a third dose? Who qualifies for one or the other?
We brought these questions to Edward Walsh, MD, an infectious disease specialist with Rochester Regional Health, to give us more insight into what the differences are and why they matter.
First of all, confusion about a COVID-19 booster shot being different from a third dose of the COVID-19 vaccine is understandable. For the mRNA vaccines (Pfizer and Moderna vaccines), the initial immunization schedule requires two doses 3-4 weeks apart - at which point you are considered fully vaccinated.
A booster dose for these two vaccines refers to a third dose, which is generally given many months later. However, for the Janssen (Johnson & Johnson) vaccine that only requires one dose in the initial vaccination schedule, a booster would be considered a second dose of this vaccine, also given many months later.
Generally a booster shot is given to someone after their initial immunity to a disease starts to drop off over time. The booster shot does what its name suggests: it gives a boost to the immune system and helps it continue protecting the body against infection.
Following reviews of recent vaccination data, the CDC issued recommendations authorizing booster doses of the Pfizer-BioNTech, Moderna, and Johnson & Johnson COVID-19 vaccines to people ages 18 and older, as their vaccine-acquired immunity to COVID-19 may be dropping off. That lessened immunity can result in increased risk of infection – often referred to as “breakthrough” infections. For those ages 12 to 17, the CDC has authorized a booster dose of the Pfizer-BioNTech COVID-19 vaccine.
Currently, those who received the Johnson & Johnson vaccine initially must wait at least two months before receiving their booster dose. Those who received Moderna or Pfizer-BioNTech need to wait at least five months.
At this time, a third dose of the fully FDA licensed Pfizer mRNA vaccine has been recommended by the CDC for certain groups of people, including people ages five and older who are moderately or severely immunocompromised. A third dose of the Moderna mRNA vaccine is recommended by the CDC for people ages 18 and older who are moderately or severely immunocompromised. Both third doses, according to current CDC guidance, are recommended 28 days after the second dose.
Different groups of people qualify for each kind of shot.
The CDC is authorizing booster shots for anyone ages 12 and older who has been fully vaccinated with two doses of the Pfizer-BioNTech for five months, for adults over age 18 who have been fully vaccinated with two doses of the Moderna vaccine for six months, and for those ages 18 and older who received their first dose of the Johnson & Johnson vaccine at least two months ago.
The CDC and FDA recommend a third dose of the Pfizer or Moderna COVID-19 vaccine be given to people with “moderately to severely compromised immune systems.” Some of these immunocompromised people include:
The guidelines regarding the benefit and safety of mixing different vaccines are different for initial immunization, booster shots, and third doses.
On October 21, 2021, the CDC issued new guidance that allows for any COVID-19 vaccine with emergency use authorization to be used as a booster shot - regardless of what the person had as their initial two doses (or single dose, if they were given the Johnson & Johnson vaccine).
When it comes to third doses of the Pfizer or Moderna vaccine, experts say attempts should be made to match the third dose to the original two-dose vaccine. However, if that same type of vaccine is not available, patients can have another mRNA vaccine administered, according to the New York State Department of Health.
For example, if a person received the two-dose Pfizer vaccine and is eligible for a third dose but only additional doses of the Moderna vaccine are available at a location, they can receive the third dose of the Moderna vaccine.
Mixing and matching initial immunization doses (i.e., a first dose of Pfizer and a second dose of Moderna) remains under study at this time.
Rochester Regional Health is offering booster shots and third doses of the COVID-19 vaccine to our patients. Anyone who wishes to obtain a booster shot or third dose can contact their primary care provider. Most of the available doses are the Pfizer vaccine.
Monroe County Public Health will be taking appointments for booster shots several locations, including the Monroe County Fleet Center in Chili, Pittsford Plaza near Century Wines, the Mall at Greece Ridge, and the Monroe Community College Downtown Campus in Rochester. Appointments can be made by calling (585) 753-5555 or visiting the Monroe County Public Health website.
A list of pharmacies and public health agencies offering booster doses or third shots is also available on the Finger Lakes Vaccine Hub website.
If you have questions about whether you should receive either a COVID-19 booster shot or a third dose of the COVID-19 vaccine, contact your primary care provider.
With information and misinformation abundant online, we took the time to bring some of the most common questions about the vaccine to our expert doctors and researchers.Schedule An Appointment
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