How to choose a COVID-19 vaccine booster shot

vials of covid-19 vaccines
Image: Now that people can mix and match COVID-19 vaccines, choosing one for a booster dose may be complicated. Reviewing the data on and talking to scientists about the vaccines from Pfizer/BioNTech, Moderna, Johnson & Johnson and AstraZeneca (not available in the United States)  can help inform that decision. (

Over the weekend, I received a phone call from my state health department reminding me that I am eligible for a second dosage of the COVID-19 vaccine from Pfizer and its German partner BioNTech. However, do I really need a third COVID-19 shot? If so, which of the three recommended vaccines in the United States should I get? My judgment was based on evidence and consultations with specialists. I learned a lot about boosters that could be helpful to others. To begin, let’s begin with J & J. U.S. health regulators and specialists recommend that everyone who received this vaccine as their first vaccination obtain a booster two months later (SN: 10/19/21). As a result of this, the antibody response from the one-dose vaccine is lower than for Pfizer and Moderna’s two-dose mRNA vaccines. “It doesn’t go away completely,” says Sachin Nagrani, medical director of Heal, a startup that provides primary healthcare in people’s homes via telehealth visits and house calls. However, “it seems like your immune response is less protective” a few months after the J&J injection. Few studies have been done on the J&J boosters, but AstraZeneca’s vaccine, which is based on the same technology but is not currently accessible in the United States, could provide some insight (SN: 11/23/20). There are two vaccines that use adenoviruses to transmit coronavirus spike protein DNA instructions to cells. COVID-19 vaccine was more successful when it was combined with a Pfizer shot (or sometimes the modern version Moderna) than it was when AstraZeneca’s vaccine was given alone.

In Sweden, for example, a double dose of AstraZeneca was only approximately 50 percent effective in avoiding symptoms. AstraZeneca enhanced with Moderna was 79 percent effective, according to a study published in the Lancet Regional Health – Europe on October 18. First-dose J&J vaccine recipients who received an mRNA vaccine as their second dose acquired much more antibodies than those who received another J&J injection. Consider an mRNA booster for J&J vaccinators, according to these findings. U.S. Food and Drug Administration approval for mRNA boosters was granted on November 19. In several places, adults were already permitted to be boosted before the FDA’s announcement. CDC director Rochelle Walensky signed off on the extended suggestions later that day after an advisory council for the US Centers for Disease Control and Prevention provided its unanimous approval. Experts doubt whether the increased doses are necessary for most people. Before determining whether or not to get the shot, I weighed the risks. For persons 65 and older, who are at risk of serious disease and death from COVID-19, boosters were recommended. People 50 and older should obtain a booster, according to the CDC panel. I’m younger than that. Those between the ages of 18 and 49 may receive a third dose, but they don’t necessarily need an additional injection like I and other middle-aged and older people need. COVID-19 boosters have also been recommended for those who work or live in areas with a high risk of exposure. In contrast, I work from home, where my husband and I are the only people in our house. People with preexisting health issues are more likely to suffer from serious illness. However, I have a few medical issues that increase my vulnerability. If I were to have a booster shot, how much more benefit would I get than the two doses I’ve already received?

As a result of data obtained in Israel since the end of August, much of what we know about mRNA booster shots may be traced back to that country. Fewer than three in a hundred thousand healthy patients who had two doses of the vaccination developed severe COVID-19 or required hospitalization after receiving the vaccine, according to a study published in the Lancet on October 29th. However, the number began to rise as a result of underlying health issues. 82 persons out of every 100,000 people who were properly vaccinated had serious illness. 503.5 out of every 100,000 people had three or more health hazards. Severe disease rates for those with one or two health conditions were reduced to 3.2 per 100,000, while the rate for those with three or more health conditions was reduced to 51.6 per 100,000. This information suggests to me that I need a booster. The risk-benefit ratio may be different for young, healthy individuals. According to Nagrani, patients in this scenario can wait until additional data is available on the vaccine’s long-term efficacy before having a booster vaccination. It is, however, recommended that adults over 65 and those with medical issues or who reside in assisted-living facilities have a booster. What’s the next step in the process? Booster shots can now be given in any combination of immunization doses. Moderna or J&J are viable alternatives to Pfizer. First and foremost, I ask myself: What am I trying to accomplish? That being said, I’d wish to avoid being infected with COVID-19 at all costs. There is no “sterilizing immunity” provided by any of the COVID-19 vaccinations. All of them, however, offer some measure of immunity from disease. The mRNA vaccines appear to be the best option at first appearance, but I’ve been intrigued by the recent FDA and CDC advisory board meetings regarding the multiple forms of immunity that vaccines can create. MRNA vaccinations provide massive amounts of antibodies that prevent the coronavirus from infecting cells. However, vaccines based on adenoviruses, such as those produced by J&J and AstraZeneca, appear to be superior at generating long-lasting immunity against T cells. An adenovirus-based vaccination like J&J’s may have certain advantages if combined with an mRNA vaccine.

Vaccines from Pfizer or AstraZeneca with a Pfizer chaser were given to trial participants in France. Research published on October 21 in Nature found that the risk of coronavirus infection was twice as high in people who received Pfizer for both doses. Of the 2,512 persons (0.39 percent) who received the mixed doses, 10 became infected, while the 10,609 people (0.76 percent) who received Pfizer alone had 81 become infected. The study’s co-author, Jacqueline Marvel, an immunologist at the International Center for Infectious Disease Research (CIRI) in Lyon, France, advised me to switch to J&J for my booster shot in order to raise my T cells. In order to boost the T cell response, she questioned if it was worth changing the vaccination. I was a little taken aback by that response, given that Marvel’s day job involves studying T cells. Defending her position, “I’m pro-T cell. Neutralizing antibodies are, however, the first thing that should be obtained. Antibodies work considerably faster than T cells to protect you because they block virus entry into cells. “Antibodies are what you want if individuals don’t want to get sick and show symptoms.” Additionally, mRNA vaccinations are a great approach to boost the body’s immune response.

However, there is some evidence that the side effects seen after a booster may be milder than those encountered following the second dose. Uncommon side effects including myocarditis (inflammation of the heart muscle) after an mRNA dose, particularly for young guys following the second dose, cause some people concern. However, this is a rare complication: The number of Israelis who experienced myocarditis or pericarditis after receiving a Pfizer booster shot was reported to be 17 out of 2.5 million (SN: 10/19/21). I’m not a young man, and the only negative effect I experienced from my first two doses was a sore arm, so I’m not too concerned about that. That’s enough to persuade me to have an mRNA injection. Which one, though? It was a matter of expediency that led to this conclusion. I went on the internet to look for a location to get a booster. The Moderna vaccine (and even fewer J&J shots) are hard to come by in my neighborhood’s grocery stores, pharmacies, and other vaccination providers, while Pfizer dosages are numerous. Consequently, I received a flu vaccine and a Pfizer booster shot in my right arm. There is no risk in taking them together.) The CDC says I’m not the only one. Pfizer was the vaccine of choice for nearly all those who were completely vaccinated and needed a booster shot. Even if my arms hurt for a little while, it’s a little price to pay to avoid getting sick and to help keep people around me well.


Categories: Clinical