Initial shipments of tailored coronavirus booster shots arrived in Washington this week. Made by Pfizer and Moderna, they use the same messenger R-N-A technique of the original coronavirus vaccines released in 2021, but they are designed to fight the original Covid strain and the newer omicron variants.
We wanted to know more about these booster shots, called “bivalent” boosters. So we spoke to Dr. Francisco Velazquez, health officer for the Spokane Regional Health District. What follows is an edited version of Dr. Velazquez’s conversation with SPR’s Brandon Hollingsworth.
What are bivalent vaccines?
“Vaccines can have more than one component. If you think about flu vaccines, we typically look at what are the most common strains of the flu…and on the basis of that, the vaccine is manufactured against those. As a general rule, the flu vaccine is quadrivalent – meaning it works against four strains.
“The original [coronavirus] vaccine was monovalent. It was manufactured against the original strain. It’s a great vaccine. It has worked very well.
“The current [bivalent] booster is half ancestral and half newer strains. And that will provide us protection as we go from the fall into the winter, because we do know that respiratory illnesses tend to increase in the fall and winter. So our goal is to provide this bivalent booster to prevent transmission in the fall and winter.”
In early 2021, the initial vaccine doses were allotted to make sure first responders, immunocompromised people, senior citizens and others could get their shots first. Should healthy people wait a bit before getting a bivalent booster?
“The initial shipment to the state of Washington is slightly over 191,000 doses, which is a lot more than we ever saw in the early shipments [in 2021]. For an initial shipment, that’s a good quantity.
“It’s always important to know your level of risk…of transmission and also your risk for severe disease. So that’s a conversation that individuals need to have with their provider. Because my provider knows me better than anyone else, and I can’t really tell anyone specifically what they should do.
“At this point in time, the only specific guidance we have is based more on age groups. And that is which bivalent booster you can get. If you’re 18 or older, technically, you can get either the Pfizer or the Moderna. If you are 12 to 17, you’re basically qualified for the Pfizer bivalent booster. If you are four to 11, most of those children are completing or have completed their primary dose, so right now, the recommendation is to use a monovalent booster on them. And the last group is six months to four years of age. There’s no recommendation for boosters at this point in time for that age group, though they do qualify for the primary series.
“[However,] one of the reasons we saw an increase in hospitalizations among senior citizens [during recent surges] is because those individuals are probably ones whose primary series and boosters have been the longest [ago], so they’ve entered the area of immune response decrease. So if I was a primary care provider taking care of a senior member of the community, I would probably recommend that they get the booster as soon as possible – provided their last dose of vaccine was two months ago. That’s the parameter to keep in mind.”
Can I get a booster shot at the same time I get a flu vaccine?
“Based on the science that we have behind the Covid vaccines – including the bivalent boosters -- you can co-administer [the shot], for those that are clinically able to do so. I bring this up because people will think about their flu shot in the next month, month-and-a-half. And may not be thinking about their booster shot. So I think it’s important to keep both in mind. It doesn’t mean you have to get them at the same time, only that you can.”
Pfizer and Moderna make these bivalent boosters. Should I match the booster to the maker of my original vaccine?
“If you’re 18 or older, you can get either one. It doesn’t matter which your primary series was.”
What if I haven’t been vaccinated at all? Should I go ahead and get a booster as a shortcut?
“If you have not been vaccinated at all, you need to get your primary series. And then you have to wait two months [before getting the bivalent booster].
“Another question we get is, ‘I just had symptomatic Covid. What should I do?’ Right now, the recommendation is wait about three months – with one caveat. And the caveat is, if we start to see areas of high transmission, then we will recommend waiting [only] two months. So there’s a little bit of clinical decision-making that needs to happen. And that’s why I always encourage people to talk to your provider, because we’re all slightly different and making blanket statements makes it complicated for people to follow.”
The CDC recommends getting flu shots by the end of October. Do I need to get my coronavirus booster shot by a certain date on the calendar?
“The flu has been around a long time, and it has a seasonality that is predictable. We know between October and May, that’s when flu season is going to peak. So it’s recommended that you get your flu shot in the fall, just to make sure you’re protected…when we see more transmission.
“With SARS-Cov-2, the virus that causes Covid-19, we have not seen a predictable seasonality as of yet. Which is one of the reasons it’s still considered pandemic and not endemic. There’s no specific time when the boosters are recommended, but one of the reasons for the release of the boosters at this particular period in time, is that a lot of the modeling projects we may see an increase in cases, fall into winter…so the goal was to release these boosters before we hit that season, so people could start to protect themselves and prevent some of the cases we could [otherwise] see in the fall and winter.”
