COVID-19
When a person receives a vaccine dose, their body’s immune system acquires protection against a specific type of illness – e.g., influenza, polio, COVID-19, etc.
Depending on the vaccine and how effective it is, health providers may need to give another dose of the vaccine to help ‘boost’ a person’s immune system.
Edward Walsh, MD, an Infectious Disease specialist with Rochester Regional Health, and Syed Mustafa, MD, an immunologist with Rochester Regional Health, have insight into the research about boosters for the COVID-19 vaccine.
On August 18, 2021, the U.S. Department of Health and Human Services and Centers for Disease Control and Prevention (CDC) issued a statement, saying certain people in the U.S. who are fully vaccinated against COVID-19 will be able to obtain a booster shot.
Since then, the FDA and CDC have reviewed thousands of pages of data and expanded the emergency use authorization (EUA) for all three available COVID-19 vaccines in the U.S. - Pfizer-BioNTech, Moderna, and Janssen (Johnson & Johnson).
The recommendation was made based on evidence that protection against the virus "could diminish in the months ahead, especially among those who are at higher risk or were vaccinated during the earlier phases of the vaccination rollout," according to the CDC.
There are a small number of cases in which people who are fully vaccinated do contract COVID-19. But for those patients, the symptoms will look more like a common cold or bronchitis and won’t become severe.
“For severe disease, hospitalization, pneumonia, deaths, and so forth - at this point - the vaccines are holding up extremely well," Dr. Walsh said. Of the 166 million people in the US who are fully vaccinated there have only been 8,000 COVID related hospitalizations, and many have been asymptomatic or very mild and not thought to be the reason for hospitalization. Data just reported by the New York State Department of Health indicates that vaccine efficacy against hospitalization remains above 90 percent in vaccinated persons.
The CDC has authorized the Pfizer-BioNTech COVID-19 vaccine to be used as a booster shot for all individuals ages 5 and older who have been fully vaccinated for a period of five months. A person is fully vaccinated two weeks after their second dose of the vaccine was administered.
For the Moderna vaccine, anyone over the age of 18 who is fully vaccinated can receive a booster shot five months later.
For the Janssen (Johnson & Johnson) vaccine, anyone over the age of 18 who received their first dose can receive a booster shot two months after they were fully vaccinated.
Under the latest guidance, any fully vaccinated adult can receive a booster shot using any of the three available vaccines. In these "mix and match" scenarios, an eligible person who received two doses of the Pfizer vaccine may receive a booster shot of the Pfizer, Moderna, or Johnson & Johnson vaccine. Any person who received their Johnson & Johnson vaccine dose may choose to receive a booster shot of Johnson & Johnson, Pfizer, or Moderna. For fully vaccinated children ages 5-17, the Pfizer-BioNTech is the only vaccine that can be used as a booster shot.
On August 12, 2021, the Food and Drug Administration issued an update to its emergency use authorization for the Pfizer-BioNTech and Moderna COVID-19 vaccines, allowing a booster shot for certain people who are immunocompromised.
The new guidance will "allow for the use of an additional dose in certain immunocompromised individuals, specifically, solid organ transplant recipients or those who are diagnosed with conditions that are considered to have an equivalent level of immunocompromise." The additional dose would be administered at least 28 days after the second dose of the vaccine was administered.
There are an estimated seven million Americans who would qualify as immunocompromised based on eligibility criteria. These individuals create lower levels of antibodies from COVID-19 vaccines as compared to people without immunocompromising conditions.
"Early studies have shown that a 3rd dose of a COVID vaccine in patients with organ transplant increases the immune response and leads to higher levels of antibodies against COVID. This information likely applies to blood cancers as well," Dr. Mustafa said.
The Pfizer vaccine is approved for individuals ages 5 and older; the Moderna vaccine is approved for those ages 18 and older. The FDA also advises close contacts of immunocompromised people to get vaccinated to protect their own health and the health of their immunocompromised loved ones.
On August 13, 2021, the New York State Clinical Advisory Task Force adopted the guidance and authorized providers to make certain immunocompromised individuals eligible for a booster shot.
The use of the term “booster” implies the need to boost the immune response at specific intervals. For example, some booster shots might be administered every 8-12 months. Since our immune system learns and remembers how to fight specific pathogens, antibodies usually last far beyond 8-12 months. In fact, most antibodies last for many years.
"The term “booster” is a bit misleading, since frequent doses, such as annually, are unlikely to be necessary," Dr. Mustafa said. "It is more likely this 3rd dose represents a 3-dose series of vaccination, which will hopefully provide long lasting immune protection. This is similar to what is already done with certain childhood vaccinations, such as hepatitis B."
Medical providers administer booster shots in cases where data and peer-reviewed research shows the need for additional protection for a person’s immune system.
There are several booster shots currently recommended by the Centers for Disease Control and Prevention, including the tetanus, diphtheria, and pertussis (Tdap) vaccine. Experts recommend adults get this particular booster shot every 10 years.
A study currently underway by scientists with Rochester Regional Health and University of Rochester Medical Center could help experts further understand how mRNA vaccines invoke an immune response.
“We've been giving booster doses in our research study to look at the effect of the extra booster dose,” Dr. Walsh said. “One: how well is it tolerated and we've learned that it is well tolerated. And secondly, we've also been able to demonstrate that it raises antibody levels quite substantially, even well above those that were obtained after the first two doses. So if you really do need a booster dose, I think we are in a very good position to move forward in that regard.”
