More people can now get second Covid-19 booster shots after federal health officials announced they are allowing a broader group to get fourth doses of the two messenger RNA Covid-19 vaccines made by Pfizer/BioNTech and Moderna.
Adults 50 and older, who received three previous mRNA doses, can get a second booster dose if it’s been at least four months since their first one. Everyone who received two doses of the Johnson & Johnson vaccine can also receive an additional mRNA dose four months after their last booster.
Many people are wondering: Does it mean everyone is going to need an annual Covid-19 booster? Do we need booster shots even more frequently? Is it going to be combined with the flu shot? Are new vaccines going to be developed that target new variants? And should they wait to get the booster if they are eligible, or get it now?
To help answer these questions, I spoke with CNN Medical Analyst Dr. Leana Wen, an emergency physician and professor of health policy and management at the George Washington University Milken Institute School of Public Health. She is also author of “Lifelines: A Doctor’s Journey in the Fight for Public Health.”
CNN: Will everyone need a Covid-19 shot every year?
Dr. Leana Wen: We don’t know yet. There are a lot of variables here, and only time – and ongoing research – will tell.
First, we don’t know how long the immune protection from the vaccine and first booster will last. There is a lot of evidence that the first booster is very important. During a time when Omicron was the dominant variant, the effectiveness of three doses against severe disease remained high, at 94%, according to a study by the US Centers for Disease Control and Prevention. If this protection starts waning substantially, that would be a sign that another booster is needed.
Second, there may be new variants that develop over time. The influenza vaccine is given annually after it’s reconfigured every year for new mutations. The current vaccines work well against the Omicron subvariants, but if there are future variants that evade vaccine-induced immunity, that’s another reason for additional vaccinations.
Third, we need to monitor for how prevalent Covid-19 is. Right now, it is still rampant throughout the world, but if it ends up fading, regular booster doses may not be needed. As Dr. Anthony Fauci, President Joe Biden’s chief medical adviser, said to CNN, “Will it ultimately get to such a low level that we might not even need a boost every year?” That’s possible, but we don’t know yet.
Fourth, we need to see whether there is a clear seasonality to future Covid-19 outbreaks. Other coronaviruses that cause the common cold are more prevalent in the winter, as are other respiratory viruses like RSV (respiratory syncytial virus) and influenza. It’s likely that SARS-CoV-2 is, too, and there have been surges during winter months. This part, though, still needs to be seen in this coming fall and winter seasons.
Finally, there are logistical considerations to think about. Adding an annual vaccine is a big undertaking. The uptake of the influenza vaccine is already low; just only about half of Americans get it every year. With the misinformation and polarization around Covid-19, encouraging this level of frequency will be a big undertaking.
CNN: Right now, a second booster is already allowed four months after the first, which means that the current frequency is more than once a year. Could boosters be needed even more than once a year?
Wen: It’s possible. I want to emphasize that there is a lot we don’t know, simply because we don’t have the ability to foretell the future.
There are a couple of different scenarios that could occur. One is that certain groups of people may need more frequent vaccines. Recall that people who are moderately or severely immunocompromised have been recommended to get their additional booster for months. It’s possible that, going forward, certain more vulnerable populations will be recommended to get vaccines at a higher frequency than the general population.
In addition, there will also need to be contingencies if a new variant arises that evades prior immunity. There should be the option to develop, manufacture and quickly distribute variant-specific vaccines. If this happens, the frequency could end up being more than once a year for a particular time period.
Going forward, we have to consider the availability of other therapies and mitigation measures, too. For example, Evusheld is an antibody infusion that, when given to immunocompromised individuals, is very effective at reducing their likelihood of progression to severe illness. Antiviral pills and monoclonal antibodies are effective treatments when given early in the course of illness. And there are other preventive measures, including masking and testing before get-togethers, that can reduce risk, too.
CNN: If the Covid-19 vaccine is going to be given annually, would it make sense to combine it with the flu vaccine?
Wen: In theory, yes, but we just don’t know if the Covid-19 vaccine needs to be an annual shot.
There are other vaccines that last longer. The Tdap (tetanus-diphtheria vaccine), for example, requires a booster every 10 years. The polio vaccine is a four-dose vaccine – you get four doses, and you’re done. Hepatitis B is a three-dose vaccine.
It’s possible that Covid-19 could be three or four doses, and we’re done, or it may need to be updated more frequently like influenza. Again, we just don’t know yet. If it does end up being something that’s annual, and the seasonal pattern appears similar to influenza, then having a combined shot – or at least, getting it at the same time as the flu shot – would be sensible.
CNN: Why aren’t there variant-specific vaccines that target Omicron?
Wen: Scientists are working on these vaccines now. They are testing Omicron-specific vaccines and boosters to see if they could be even more effective than the original vaccines, which were targeting the previously dominant variants.
One consideration is that additional variants may arise, and scientists have to think about whether the Omicron-specific vaccines or the original vaccine – or some combination – will be most likely to be effective against potential variants in the future. This was among the many issues that advisers to the US Food and Drug Administration discussed in their meeting this week.
CNN: If people are eligible for boosters now, should they get them, or should they wait?
Wen: It depends on the individual’s medical circumstance and how much they are willing to give up to avoid Covid-19, as I mentioned in our CNN Q&A last week. Someone who is over age 65 and/or immunocompromised should probably get the additional booster now.
On the other hand, someone who is between ages 50 and 65, with no medical problems and recently had an Omicron infection, could probably wait. Some people might defer an additional booster as long as they are well-protected against severe illness. Others want to avoid any infection, even mild and asymptomatic infections. These are all personal decisions to be made in consultation with your medical provider.
CNN: What’s your booster advice for people under 50? Should people get their first booster? And should they go for their second?
Wen: Everyone should get their first booster if eligible. The question of the second booster is more complex. If the person is under 50 and moderately or severely immunocompromised, they should also get their second booster. Another group that should get their second booster, even if they are under 50, are those who received two doses of the Johnson & Johnson vaccine, and it’s been at least four months since their last dose. All other groups under 50 are not eligible to receive their second booster at this time and should not go for their second.