• The Centers for Disease Control and Prevention (CDC) approved a second COVID-19 booster shot of the messenger RNA (mRNA) vaccines for people over 50 years old and those who are immunocompromised.
• People with breast cancer should talk with their oncology teams about whether they should time any booster shots around cancer treatments.

The CDC and U.S. Food and Drug Administration (FDA) have authorized and recommended a second COVID-19 booster shot for people 50 and over and those with immunocompromising conditions. The American Society of Clinical Oncology states, “Vaccination, including the use of booster doses and the use of different vaccines across doses, should take place according to current US CDC and FDA recommendations.”

People with breast cancer are generally considered immunocompromised, which can lead to an increased risk of severe disease and hospitalization with COVID-19. The new public health recommendations come after recent studies showed an immune response to the Moderna and Pfizer-BioNTech vaccines in many immunocompromised people, including individuals with cancer.

The New Recommendations

Some important details about these recommendations include the following:

• This booster is for people who received their first booster at least four months ago.
• This fourth shot would be either the Moderna or Pfizer vaccines, not the Johnson & Johnson vaccine.
• Even if you were previously vaccinated with the Johnson & Johnson vaccine, it is now recommended that this next dose be a Moderna or Pfizer vaccine only.
• For those who are immunocompromised and received a three-dose primary vaccination followed by an initial booster, this additional booster counts as a fifth shot.

How Booster Shots Can Protect People With Breast Cancer

If you have been diagnosed with breast cancer and are on the fence about whether to get vaccinated (or boosted) to protect against COVID-19, you may be wondering what scientists suggest. “Experts recommend that most people diagnosed with cancer or who have a history of cancer should get a COVID-19 vaccine,” Breastcancer.org advises. “Still, you should talk to your doctor about whether getting a COVID-19 vaccine and booster shots is the right decision for your individual situation.”

When it comes to booster shots, one review of previous studies found that people with solid tumors were able to raise their immune response against the COVID-19 omicron variant from 48 percent after their initial vaccinations to nearly 89 percent after a third vaccine dose. Breast cancer is one type of solid tumor cancer.

Your oncologist might advise timing your booster shot around your breast cancer treatments, so it’s important to consult with your providers before scheduling your vaccine appointment.

“I got my booster shot before radiation,” wrote one MyBCTeam member. “No issues at all.” Another wrote, “I got my booster last Monday — no side effects!”

Response to the Moderna Vaccine

The CDC’s latest recommendations follow promising new results about the effectiveness of the vaccines in immunocompromised people. A recent study from Moffitt Cancer Center included people diagnosed with solid tumors, as well as individuals with blood cancers. Researchers tested levels of antibodies, the proteins the immune system makes to help destroy a target. In this case, the antibodies were to SARS-CoV-2, the virus that causes COVID-19, made in response to the Moderna COVID-19 vaccine.

On average, antibodies against the coronavirus were identified after the second vaccine dose in about 90 percent of the participants. About 98 percent of people with solid tumor cancers showed an antibody response.

Response to the Pfizer Vaccine

Although this recent study included only people given the Moderna vaccine for COVID-19, other research has looked at immunocompromised individuals’ responses to the Pfizer vaccine. The two vaccines are based on the same technique, using a molecule called mRNA to teach cells how to make a protein that will trigger an immune system response and help prevent infection with SARS-CoV-2.

In one study that included individuals with medical conditions that caused them to be immunocompromised (including breast cancer), immune system response was about 67 percent. However, individuals with solid malignancies made antibodies after vaccination about 83 percent of the time, according to the study results.

Why These Results Matter

Additional doses of mRNA vaccines may be effective at increasing detectable antibodies in a way similar to that of the first and second doses. Other research indicates that antibody levels are likely to decrease over time, so getting booster doses at recommended intervals is necessary even in vaccinated people who made antibodies after their initial shots.

Simply making antibodies does not always translate to complete immunity from COVID-19 infection, but the findings from these studies are a good sign that the mRNA vaccines for COVID-19 can trigger strong responses even from compromised immune systems. It’s evidence that vaccines can protect people at higher risk from severe infections.

According to the CDC, getting vaccinated is still the best way to protect yourself and slow the spread of the virus.

Find Your Team

MyBCTeam is the online social support network for those with breast cancer, their caregivers, and their loved ones. Here, you can connect with other people who understand life with breast cancer. Members come together to ask questions, give advice, and share their stories with others who understand.

Are you planning to get another booster vaccine? Do you have concerns about vaccine effectiveness, vaccine response, or time of vaccination? Share your insights in the comments below, or start a conversation by posting on MyBCTeam.