Friday, 9 Dec 2022

COVID-19 booster now or wait: Experts answer key questions

COVID-19 vaccines reduce the risk of infection, hospitalization, and death caused by the SARS-CoV-2 virus. While mRNA vaccines continue to provide durable protection against severe outcomes from all COVID-19 variants, data shows that immunity against emerging variants can wane over time.

Recent research found that the current dominant SARS-CoV-2 variants, BA.4 and BA.5, are significantly more resistant to current mRNA vaccines than the previous BA.2 Omicron subvariant.

The Centers for Disease Control and Prevention (CDC) recommends getting a booster shot for everyone over 5 years old to overcome waning protection. The agency also recommends a second booster shot for immunocompromised individuals over 12 years old and those over 50.

However, current booster shots use the same formulations as the original COVID-19 vaccines for the alpha variant.

The Food and Drug Administration (FDA) recently recommended including a SARS-CoV-2 Omicron component in COVID-19 booster vaccines for the 2022 fall and winter seasons.

Pfizer and Moderna have announced the development of new vaccines targeting BA.4 and BA.5 to be ready for distribution by fall.

Some may wonder whether to get a booster shot this summer or wait for the updated shots. To help answer some of the key questions, Medical News Today spoke with six experts across multiple medical fields, including immunology, microbiology, and critical care.

Should people get another vaccine shot now or wait?

“Those who have medical conditions that predispose them to severe COVID perhaps should not wait,” noted Dr. Fady Youssef, a board certified pulmonologist, internist, and critical care specialist at MemorialCare Long Beach Medical Center in Long Beach, California. “With the current variant gaining dominance and showing its high transmissibility now may be the best time to get a second booster.”

Nicola Stonehouse, Ph.D. FRSB FRSA, Professor in Molecular Virology at the University of Leeds, told MNT:

“If eligible, it is always a good idea to take the opportunity of an additional vaccine dose. It is especially important for older people and those who are clinically vulnerable.”

“Although SARS-CoV2 is not my direct area of research, I personally got a booster because of the rise of the variants,” said Brian J. Akerley, Ph.D., Associate Professor of Cell and Molecular Biology at the Center for Immunology and Microbial Research at the University of Mississippi. “Basic principles of immunology would indicate that boosting can increase antibody and T-cell responses against parts of the spike protein that are similar in multiple variants.”

“I would have preferred a booster corresponding to the most prevalent variant, but prevention only works if done in advance. Given persistently high transmission rates and the growing evidence of long-term health effects even after the resolution of COVID, I think it is common sense to get some protection before one gets infected, rather than gambling on avoiding exposure while waiting for an improved vaccine,” Prof. Akerley added.

“If people haven’t been vaccinated yet, they should go ahead and get the immunization,” John Bates, Ph.D., Scientific Director at the Human Immunology and Inflammation Biomarker Core Laboratory at the University of Mississippi told MNT, “If a person has been vaccinated, to include the recommended booster dose(s), then they should wait.”

What if someone already had a shot or infection 3-6 months ago?

MNT spoke with Dr. Dana Hawkinson, infectious diseases and medical director of infection prevention and control at the University of Kansas Health System.

“If you have had an infection, you likely have gained what many call ‘hybrid immunity,’ which includes vaccination and infection. Infection also helps you garner immunity to other parts of the virus, not just spike, which is the component of the vaccines,” Dr. Hawkinson said.

“Nonetheless, the recommendation is that if it has been more than 4 months from your last vaccine dose/booster, you should get the second booster if you are over 50 years old or immunocompromised,” he explained.

“If you have had the infection, there is still a recommendation to get a booster if you fall into the category of requiring a booster. You may get the vaccine dose as soon as your isolation ends from the acute infection; however, waiting 2-3 months is reasonable too,” Dr. Hawkinson added.

Dr. Bates explained that waiting for the updated shots may be a good idea for certain individuals with recent vaccination or natural infection. However, unvaccinated individuals, whether they had previously contracted the SARS-CoV-2 virus or not, are recommended to get the COVID-19 vaccine as soon as possible.

“If someone is 3-6 months out from the last recommended dose of vaccine, then they don’t need another vaccination,” explained Dr. Bates, “However, even if an unvaccinated person was previously infected, it would be best for them to get the vaccine now.”

“Viruses have evolved ways to evade the immune response, and respiratory viruses, in particular, have long been known to re-infect previously infected individuals. Vaccines, by contrast, are designed to elicit strong immune responses to provide (hopefully) longer-lasting immunity,” he noted.

Dr. Youssef agrees that the advice differs for people who have yet to receive their first doses of the COVID-19 vaccines.

“People who get COVID and are unvaccinated have a higher likelihood of getting COVID again when compared to those who had COVID and got vaccinated,” said Dr. Youssef, “In addition, it seems this current variant evades the immunity that many have had from the prior infections. The CDC recommends waiting 3 months after an infection.”

What are the pros and cons to consider?

“We know that [currently available COVID vaccines are] suboptimal against the currently circulating Omicron variants, however, protection against severe disease is still achieved. As such, booster immunization is recommended,” Jorg Fritz, Ph.D., Associate Professor of Immunology at McGill University, told MNT.

Other experts MNT spoke with agree.

“The vaccines are safe and effective, so I think the pros greatly outweigh the cons,” noted Dr. Bates, “During the Omicron wave early this year, the vast majority of individuals who died from infection or who became severely ill were unvaccinated. Vaccination greatly reduces the likelihood for a negative outcome following infection.”

“The safety of the vaccines is well documented. There are very few cons associated with the vaccines. The pros, especially those for over 60 and/or with chronic illnesses, are great. Being up-to-date with your vaccines will offer you the best chance at preventing hospitalization and severe disease.”

Dr. Dana Hawkinson

How would the advice differ for people in various age groups or with underlying health conditions?

“The clinical data show that the elderly have a much higher risk of severe illness and death,” said Dr. Bates, “It’s particularly important that older individuals be vaccinated to prevent the likelihood of severe illness or death following SARS-CoV-2 infection. Similarly, if a person is immune compromised, vaccination will maximize the body’s ability to fight infection should that person become infected.”

“If someone works in a high risk industry or a high exposure industry, I would say to check with their primary care physician about when is the right time for them to get a booster,” added Dr. Youssef.

Should anybody not get a booster vaccine? 

“People that had severe side effects or negative reactions upon vaccination with COVID-19 vaccines should discuss options with their healthcare providers, but everyone else is recommended to get the booster shot,” said Dr. Fritz.

“No boosters are recommended for those under 5,” noted Dr. Hawkinson.

What is your advice for those who are reluctant to get vaccinated or a booster? 

“New variants are still arising, and the length of protection is not as long as we’d like, but vaccination is the reason that the pandemic didn’t claim more lives,” said Dr. Stonehouse, “COVID-19 infection can still be very serious, especially in pregnancy.”

“During the Omicron wave, vaccines did a great job of preventing severe illness and death despite significant changes in the Omicron variant relative to the vaccine strain, so even with changes in the virus, the vaccines are effective,” said Dr. Bates.

“Most of the published data have examined the effects of changes in the virus on the efficacy of the antibody response to vaccination. However, T cells are also important in responding to infection and likely account for the reduced severity of illness in vaccinated individuals who are infected with one of the newer variants.”

– John Bates, Ph.D.

“If your last shot was more than 6 months ago and you are 60+ or immunocompromised, it is strongly recommended to get the booster shot now,” concluded Dr. Fritz, “The booster still protects from severe disease.”

“It feels like it is never-ending,” said Dr. Youssef, “But the only thing within our control is how to protect ourselves and our loved ones. I would adhere to the CDC guidelines, and if one is eligible for a booster now they should get it.”

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