The past three years have taught us a hard truth: Covid-19 doesn’t pose the same risk to everyone it infects. Now, American public health agencies are trying to align Covid-19 vaccination recommendations with that fact.
This week, the Food and Drug Administration (FDA) and the Centers for Disease Control and Prevention (CDC) Advisory Committee on Immunization Practices rolled out streamlined vaccine recommendations aimed at helping people figure out what to do right now.
Specifically, the guidance elevates the bivalent vaccine — introduced last fall as a tool to train immune systems to protect from both older and newer strains of the virus — from “booster” status. Under the new recommendations, the bivalent vaccine can be used as the first and only shot a person gets as their primary vaccine.
The new guidance applies to the updated, bivalent formulations of the mRNA vaccines produced by Moderna and Pfizer-BioNTech. The original vaccine series most Americans received earlier in the pandemic is no longer available: Earlier, monovalent formulations from Moderna and Pfizer are no longer authorized in the US, and others, like Novavax and Johnson and Johnson’s, have been used here only infrequently.
The upshot: For now, to be considered up-to-date, everyone should have at least one bivalent vaccine. However, only higher-risk people should be getting repeat 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 haven’t gotten any Covid-19 vaccines can get a bivalent shot.
Bivalent vaccine uptake has not been great in the US. Only 42 percent of people 65 and over — who are at highest risk for severe disease and hospitalization due to Covid-19 — have received the shot. In all, fewer than 17 percent of all Americans have gotten a bivalent vaccine. In a statement, FDA’s Center for Biologics Evaluation and Research director Peter Marks said, “The agency believes that this approach will help encourage future vaccination.”
It’s worth noting that both the FDA and the CDC used “may” and not “should” language in much of this guidance (with one important exception). At this point, these agencies are avoiding language that suggests anyone who has already been vaccinated “should” get another. That’s because the data on repeat vaccination isn’t strong enough to support telling anyone they need to get another shot. Instead, the CDC and FDA highlight who is merely “eligible” for more doses.
Here’s the upshot of the latest recommendations.
If you’re a healthy person between the ages of 6 and 64 who’s already gotten a bivalent vaccine
This one is the simplest: The FDA said that for most people 6 and over, 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, said the CDC — it was.
But lately, the risk of hospitalization has been so low among children and adults in these age groups, and the protection repeat vaccination provided was so fleeting — lasting only about two months — that repeat bivalent vaccination would end up being minimally beneficial in this group.
If you’ve never been vaccinated or have only gotten older, monovalent versions of the vaccine
The CDC made its strongest and most explicit recommendation for people who haven’t gotten a bivalent vaccine yet — whether because they haven’t gotten any Covid-19 vaccines yet or have only gotten original, monovalent versions of the vaccine that were available before August 2022. Those people should get a bivalent vaccine now, the agency said in a press release. That goes for everyone 6 and over — and with so few Americans having yet received a bivalent vaccine, this is the category most are in.
For people still unvaccinated, the reasoning is that even though they may have some immunity against Covid-19 due to prior infection — by this point, most people have been exposed to the virus — that’s generally less protective from severe disease than the broader protection that seems to comes from being both immunized and recovered from infection.
For people who’ve only received monovalent versions of the vaccine, the rationale is that there’s 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 while very few of those strains are now circulating in the US, they’re still genetically closer to current strains than is the original virus.
Hence, 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’re 65 or older
People 65 or older can also get a bivalent vaccine now, even if they’ve already gotten 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. Over the fall and winter, those in this age group who’d received bivalent vaccines died at far lower rates than those who hadn’t. For this group, the FDA recommended waiting at least four months after the most recent bivalent dose to get a repeat dose.
If you’re moderately to severely immunocompromised and 5 or older
According to the CDC, people who are “moderately to severely immunocompromised” include those who are or are about to be treated for cancer or receive organ transplants, those with advanced or untreated HIV and certain congenital immunocompromising conditions, and those taking a variety of immunosuppressive medications.
If you are moderately to severely immunocompromised and aged 5 or over, you can also get a bivalent vaccine now, even if you’ve already gotten one. (Immunocompromised kids under the age of 5 aren’t eligible for a repeat bivalent dose under the FDA’s new recommendations because the agency didn’t have data to justify it. Several pediatricians at the CDC meeting this week expressed concern that this decision left a highly vulnerable group unprotected.)
There are a few reasons for this recommendation. For starters, 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 added layer of protection for immunocompromised people — no longer work against omicron variants and are no longer FDA-authorized except in unusual cases.
The FDA recommended immunocompromised people wait at least two months after the most recent bivalent dose to get a repeat dose. They also said people with certain kinds of immunocompromise — like those receiving or about to receive a stem cell transplant, medications that lower B-cell levels, or treatment with CAR-T cells, a certain kind of cancer therapy — can continue receiving repeat doses every two months going forward. People in this category should speak with their health care providers about what’s best for them.
Kids 6 months through 5 years old can get bivalent doses if they’re unvaccinated
Different manufacturers have different dosing regimens and different age thresholds for the pediatric versions of their bivalent vaccines: Moderna’s pediatric vaccine is given in a two-dose series for kids 6 months through 17 years, and Pfizer’s is given in a three-dose series for kids 6 months through 4 years. So when it comes to kids, it’s less complicated to talk about full versus partial series than number of doses.
According to the new guidelines, unvaccinated kids can go straight to the full bivalent vaccine series, much like healthy younger adults. Meanwhile, kids who’ve gotten the full or partial series of the older, monovalent vaccines can also get at least one dose of bivalent vaccine. (How many they get will depend on how many monovalent doses they got, and of which manufacturer. Parents should ask their pediatrician what to do for their child.)