COVID-19: What Is the Bivalent Vaccine & Who Should Get It as a Booster Dose?

In this short video, Dr. Paul Offit describes what the COVID-19 bivalent vaccines are and who might need them as a booster.


COVID-19: What Is the Bivalent Vaccine & Who Should Get It as a Booster Dose?

Hi, my name is Paul Offit. I'm talking to you today from the Vaccine Education Center at the Children's Hospital of Philadelphia. It's Friday, September 2nd, 2022. So yesterday, the Advisory Committee for Immunization Practices to the Centers for Disease Control and Prevention voted to approve the use of a bivalent vaccine, bivalent mRNA vaccine, as a booster dose for, in the case of Moderna's vaccine, everyone over 18 years of age; and in the case of Pfizer's vaccine, everyone over 12 years of age.

So, what is a bivalent vaccine and who should get this as a booster dose? So, bivalent, as the name implies, is two vaccines in one. One of the vaccines is the mRNA representing the ancestral strain, the original recipe vaccine; and the other is a vaccine, mRNA vaccine, that will protect against BA.4, BA.5, which are these Omicron subvariants that currently make up virtually all of the strains that are circulating in the United States.

So, who should get this vaccine? Well, let's go back to the beginning. If you look at vaccines when they were first used in this country, in the United States, back in December of 2020, we had two vaccines: the Pfizer vaccine and the Moderna vaccine. Now, for a year, from December 2020 to December 2021, those vaccines worked very well to prevent severe disease as a two-dose vaccine, and by severe or serious disease I mean the kind of disease that causes you to go to the hospital or go to the intensive care unit or die. And that's the goal of this vaccine — prevent severe disease. And it worked well as a two-dose vaccine for that year. But in late December of 2021, a new variant came into this country, the Omicron variant, and it was different than the other variants that were here — different than the alpha variant, different than the delta variant — different in that it was immune evasive, meaning if you'd been naturally infected or you'd been vaccinated or both, you could still get a mild disease and in some cases, you could still get a severe disease.

So, what the CDC found was that if you gave three doses, you were less likely to become hospitalized as compared to people who'd received two doses. And later they did a study showing that if you receive four doses, you were less likely to be hospitalized than those who received three doses. But the critical question is, who was getting hospitalized? Who was getting hospitalized if, for example, they'd only received two doses and not three? Who was getting hospitalized if they'd only received three doses instead of four? And the answer is not everybody. It really came down to three groups. One, were the elderly, people over 65. Two, were people who had serious medical conditions, such as for example, long-standing lung disease where even a mild infection in those patients could land them in the hospital. And the third group were people who were immune compromised.

So, I think moving forward the best way to make sense of these bivalent booster doses, which are going to be offered now in the fall and early winter, is for people who fall in those three groups to get them. Otherwise, I think a healthy young person doesn't necessarily need this vaccine.

Thank you for your attention.

Related Centers and Programs: Vaccine Education Center

Last Reviewed on Sep 12, 2022