Do I need a new Covid-19 booster? What you should know about new FDA, CDC guidance.

The last three years have taught us a hard truth: Covid-19 does not pose the same risk to everyone it infects. Now US public health agencies are trying to adapt Covid-19 vaccination recommendations to this fact.

This week, the Food and Drug Administration (FDA) and the Centers for Disease Control and Prevention (CDC) Advisory Committee on Immunization Practices released streamlined vaccine recommendations aimed at helping people figure out what to do right now.

Specifically, the guidance lifts the bivalent vaccine ̵[ads1]2; introduced last fall as a tool to train the immune system to protect against both older and newer strains of the virus — from “booster” status. According to the new recommendations, the bivalent vaccine can be used as the first and only shot a person receives as a primary vaccine.

The new guidance applies to the updated bivalent formulations of the mRNA vaccines manufactured by Moderna and Pfizer-BioNTech. The original series of vaccines most Americans received earlier in the pandemic is no longer available: Formerly monovalent formulations from Moderna and Pfizer are no longer authorized in the United States, and others, such as Novavax and Johnson and Johnson’s, have been used here only rarely.

The result: For now, to be considered up-to-date, everyone should have at least one bivalent vaccine. However, only those at higher risk should receive repeated bivalent vaccinations.

Also, while previous vaccination with the older, monovalent version of the vaccine used to be a prerequisite for bivalent vaccination, under the new guidelines, even people who have not received any Covid-19 vaccines can receive a bivalent shot.

Bivalent vaccine uptake has not been large in the United States. Only 42 percent of people 65 and over – who are at greatest risk of serious illness and hospitalization due to Covid-19 – have received the shot. In total, fewer than 17 percent of all Americans have received a bivalent vaccine. In a statement, the FDA’s Center for Biologics Evaluation and Research, Peter Marks, said, “The agency believes this approach will help encourage future vaccination.”

It is worth noting that both FDA and CDC used the language “may” and not “should” in much of this guidance (with one important exception). At this time, these agencies are avoiding language suggesting that anyone who has already been vaccinated “should” get another. That’s because the data on revaccination isn’t strong enough to support telling someone they need to get another shot. Instead, the CDC and FDA highlight who is only “eligible” for multiple doses.

Here are the results of the latest recommendations.

If you are a healthy person between the ages of 6 and 64 who have already received a bivalent vaccine

This one is the easiest: The FDA said that for most people over age 6, one dose of the bivalent vaccine, regardless of when they got it, is enough for now.

It’s not that repeat vaccination wasn’t protective against hospitalization in this age group last fall and winter, the CDC said — it was.

But recently, the risk of hospitalization has been so low among children and adults in these age groups, and the protection afforded by repeated vaccination was so fleeting — lasting only about two months — that repeated bivalent vaccination would end up being minimal beneficial in this group.

If you’ve never been vaccinated or just got older, monovalent versions of the vaccine

The CDC made its strongest and most explicit recommendation for people who have not received a bivalent vaccine yet — either because they have not received any Covid-19 vaccines yet or have only received original, monovalent versions of the vaccine that were available before August 2022. They “People should get a bivalent vaccine now,” the agency said in a news release. It applies to everyone 6 and over — and with so few Americans yet receiving a bivalent vaccine, this is the category most people fall into.

For people who are still unvaccinated, the reasoning is that while they may have some immunity to Covid-19 due to previous infection – by which point most people have been exposed to the virus – it is generally less protective against serious illness than the the broader protection that appears to come from being both immunized and free from infection.

For people who have only received monovalent versions of the vaccine, the rationale is that there is protection in the bivalent vaccine not only against the original strain of the virus, but against newer omicron variants, BA.4 and BA.5. And although very few of these strains are now circulating in the United States, they are still genetically closer to current strains than the original virus.

Therefore, a vaccine that trains the immune system to recognize both earlier and later strains of the virus is thought to provide better protection than one that only targets earlier strains.

If you are 65 or older

People 65 or older can also get a bivalent vaccine now, even if they have already had one. For this group, the rationale for the FDA’s recommendation is that people 65 and older continue to be hospitalized for Covid-19 at higher rates than younger adults. During the autumn and winter, those in this age group who had received bivalent vaccines died at a far lower rate than those who had not. For this group, the FDA recommended waiting at least four months after the last bivalent dose to receive a repeat dose.

If you are moderately to severely immunocompromised and 5 years or older

According to the CDC, people who are “moderately to severely immunocompromised” include those who are or are being treated for cancer or are receiving organ transplants, those with advanced or untreated HIV and certain congenital immunocompromising conditions, and those taking a variety of immunosuppressants . medicines.

If you are moderately to severely immunocompromised and are 5 years or older, you can also get a bivalent vaccine now, even if you have already had one. (Immunocompromised children under the age of 5 are not eligible for a repeat bivalent dose under the FDA’s new recommendations because the agency did not have data to justify it. Several pediatricians at the CDC meeting this week expressed concern that this decision left a very vulnerable group unprotected.)

There are a few reasons for this recommendation. Firstly, this group may not have as robust an antibody response to Covid-19 vaccines. But another problem is that the monoclonal antibody treatments — which used to offer an extra layer of protection for immunocompromised people — no longer work against omicron variants and are no longer FDA-approved except in rare cases.

The FDA recommended that immunocompromised individuals wait at least two months after the last bivalent dose to receive a repeat dose. They also said that people with certain types of immunocompromise — such as those receiving or about to receive a stem cell transplant, drugs that lower B-cell levels, or treatment with CAR-T cells, a certain type of cancer therapy — may continue to receive repeat doses every two months going forward . People in this category should talk to their healthcare professional about what is best for them.

Children aged 6 months to 5 years can receive bivalent doses if they have not been vaccinated

Different manufacturers have different dosing regimens and different age limits for the pediatric versions of their bivalent vaccines: Moderna’s children’s vaccine is given in a two-dose series for children from 6 months to 17 years, and Pfizer’s is given in a three-dose series for children. 6 months to 4 years. So when it comes to children, it’s less complicated to talk about full versus partial series than the number of doses.

Under the new guidelines, unvaccinated children can go straight to the full bivalent vaccine series, much like healthy younger adults. Meanwhile, children who have received full or partial series of the older, monovalent vaccines can also receive at least one dose of bivalent vaccine. (How many they get will depend on how many monovalent doses they got, and from which manufacturer. Parents should ask their pediatrician what to do for their child.)

Prepare for more changes ahead

This fall, when manufacturers are likely to release updated versions of the bivalent vaccine tailored to protect against the latest viral variants, the recommendations will likely change again.

But in the meantime, the new guidance outlines a game plan for most people on how best to protect themselves by using vaccines.