CNN  — 

Covid-19 cases are increasing across the United States once again, driven by the most contagious strain of the coronavirus yet, BA.5. Federal health officials are urging Americans to stay up to date on their vaccines by getting additional boosters if they are due for them, but many people are confused.

Who is eligible for boosters now? Will all adults be able to get a second booster soon? If new boosters are being developed for the fall, should people wait until then or get boosted now? How long should people wait for their booster after having contracted Covid-19? And what about kids — should they get boosters now or wait until school starts?

To help us navigate 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: Can you start by reminding us who is eligible for booster doses at this time?

Dr. Leana Wen: The latest guidelines from the US Centers for Disease Control and Prevention are as follows: If you are 50 and above, you are eligible for two booster doses of the mRNA vaccine (Pfizer/BioNTech or Moderna). The first booster dose is given at least five months after your primary vaccination (which is either two doses of the mRNA vaccine or one dose of Johnson & Johnson vaccine). The second booster dose is given at least four months after your first.

If you are between 5 and 49, you are eligible for your first booster dose, if it’s been at least five months since your primary series. Children younger than 5 just started receiving their initial vaccinations and therefore are not eligible for additional boosters yet.

There are a couple of exceptions. The first is if you are moderately or severely immunocompromised. Those individuals are generally able to get a third booster dose, with an interval between booster doses that’s slightly condensed compared with the intervals for people who aren’t immunocompromised. Another exception is for those who received an initial Johnson & Johnson one-dose vaccine, then subsequently got another J&J vaccine as their first booster. Those people, no matter their age, are able to get a second booster of an mRNA vaccine if it has been four months since their second J&J shot.

CNN: Will adults who are under 50 be able to get their second booster anytime soon?

Wen: Federal health officials are discussing expanding the eligibility of second boosters. My best guess is that in the next month or so, they will make at least a permissive recommendation, meaning that those who want to get another booster should be able to receive one.

The decision about who should get a booster and how often is not straightforward. At the end of the day, there is a fundamental disagreement among scientists and public health experts on the purpose of the Covid-19 vaccinations. Some believe that the goal of these vaccines is to prevent severe illness, and as long as the vaccines continue to protect against hospitalization and death, additional boosters aren’t needed. Others point to vaccines also being able to reduce symptomatic illness. That effect is not as long-lasting as the protection against severe illness, so those who hold this second point of view would advocate for more frequent boosters. The answer isn’t straightforward.

CNN: Are there certain people you’d say really need to get boosted now, if they haven’t already?

Wen: Here’s how I think about the three groups for whom boosters are more urgent if they have not received them.

A nurse preps a syringe at a pop-up Covid-19 vaccination site at the Albanian Islamic Cultural Center, April 8, 2021, in the New York borough of Staten Island.

We know that age is a major risk factor for severe illness, and also that the protection against severe illness wanes in older individuals. People 60 and older, and who are 50 and older with chronic medical conditions, should really receive the two boosters that they are eligible for.

Those who are immunocompromised and are eligible for more boosters should get them, since they, too, are among those who are most vulnerable to severe outcomes from Covid-19.

Beyond that, all adults should receive their first booster. We know that the first booster really increases protection, including against severe disease. If you are 18 and older and have not yet had any vaccines beyond your primary vaccination, you should get your booster now.

CNN: What about children? Should they also get their boosters if they’re eligible?

Wen: The data for boosting kids is much less compelling than for adults. The CDC does recommend boosters for children 5 and older, and I think a lot of parents and caregivers will want to follow that guidance. But the urgency is not the same as it would be for adults, especially older adults, who have not yet been vaccinated.

CNN: Let’s talk about timing. Some people are worried that if they get vaccinated now, they won’t be able to get the Omicron-specific vaccines that may be coming out in the fall. Should that be a reason to wait?

Wen: For most people, I don’t think this is a reason to wait. Here’s why.

First, federal health officials have said that getting vaccinated now won’t preclude you from getting an updated vaccine in the fall. It’s worth stating here that it’s not certain that these updated vaccines will become available. The one likely to become authorized is the “bivalent” vaccine, meaning that it will be a combination of the original vaccine and an Omicron subvariant vaccine.

Second, there is a lot of virus surging around now. Getting boosted now will protect you now, and if you need an additional level of protection in the fall and winter, you could get another dose then.

Third, it’s not entirely clear that the updated vaccine is going to be better than the vaccines available. The updated vaccine is intended to target the Omicron subvariants, which would be great if the vaccines were currently available, since those are the dominant variants in circulation. However, if they are going to be given in the fall, there is no guarantee that the Omicron subvariants are still going to be the main strains at that point. Of course, we hope that the updated boosters will be more effective than what we have now, but we don’t know that’s going to be the case — which is even more reason not to wait until then.

CNN: I’ve heard some people say, I’ll wait to get a booster until right before a big trip. Does that make sense?

Wen: I can understand why some people might go with this approach. The booster does enhance protection against infection for a short time period after it’s given, probably with maximal effect from about 10 days to three months. Someone who just got boosted could still contract Covid-19, but chances would be lower than if they got the booster, say, six months before.

Of course, there are other ways to reduce your risk of contracting Covid-19, too. If you are very concerned about getting the coronavirus, you should also wear a high-quality N95 or equivalent mask in indoor spaces and avoid crowded settings.

CNN: If someone has just recovered from Covid-19, how long should they wait before their booster?

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Wen: They are able to receive a booster as soon as they are 10 days past when they first started having symptoms and no longer have a fever, though I’d recommend that they wait a bit longer. That’s because recent infection conveys good protection for a short period of time and reinfection within a three-month window is rare. To get the longest protection out of your next shot, you could wait three months after your infection to get the additional booster.