I got my COVID-19 bivalent booster this week.
Not many Americans have. According to The Washington Post, about 4% of eligible people had received that dose, which was first approved barely a month ago. That’s despite widespread availability. More than 150 million doses have been ordered, and appointments to get the vaccine are widely available. Walk-ins are commonplace; I scheduled an appointment within a couple of hours at a Walgreens.
But, frankly, I get it. COVID fatigue is real and fair. Most Americans have already been infected. Going to get a shot means a new errand, potentially feeling queasy for a short while, for uncertain benefit. Is it really worth it?
So I’m here to show you the math on getting the bivalent booster — the latest one that contains a half booster dose of the original COVID vaccine and a half-dose of a vaccine formulated against BA.5, the most widespread version of omicron we’ve had this year. Why did health officials decide to approve the shot? Is the new shot worth it?
Hospitalizations with and without the bivalent booster
This is a little harder to calculate than you might think. We know that COVID vaccine efficacy reduces over time — one study estimated about 7.3% per month against infection, and about 3.4% per month for severe disease. (Remember, protection from the antibodies from previous infection wanes, too.) So the lion’s share of the benefit of the vaccine’s protection against infection is likely to be had in the next six to nine months — and we don’t know how much COVID there will be in the winter.
As a result, you have to model it mathematically. One of my first coronavirus articles was about just how difficult it is to reliably model something like a disease outbreak, because the exponential infectious nature makes errors potentially gigantic. It remains difficult, but two years of experience has taught us more about what to expect with cycles of viral spread.
One study from Canadian researchers looked at three scenarios from which government officials might choose:
• Scenario 1: No boosters given this fall and winter at all.
• Scenario 2: A booster campaign beginning Sept. 1, with a bivalent booster with half “original recipe” vaccine, and half the first omicron variant (BA.1) vaccine.
• Scenario 3: A booster campaign beginning Nov. 1, with a bivalent booster with half “original recipe” vaccine, and half the most recent omicron variant (BA.5) vaccine. This is likely to be at least somewhat more effective than the vaccine based on the older omicron version.
The idea here is to find out whether the expected increased efficacy of targeting the latest variant would be worth the delay in releasing a vaccine. Researchers found that Scenario 2 was best — that releasing a quite good vaccine earlier was better than an updated vaccine later.
Below is their estimate on the number of COVID hospitalizations they expect per month in each of the scenarios. You can see how the BA.5 vaccine helps down the road but results in more hospitalizations in the next few months.
Given this evidence of how important quick vaccine release is, the U.S. Centers for Disease Control and Prevention decided to have its cake and eat it, too. Based on preclinical studies, officials decided that the Scenario 3 BA.5 vaccine was to be released immediately, not in November.
Matthew F. Daley, chair of the advisory committee on vaccines to the CDC, looked at this and other modeling in his support of the new bivalent vaccine, which passed by a 13-1 vote. He said that “based on the modeling that we saw, there would be a cost to (waiting), and that cost might be somewhere in the range of 9,700 deaths and 137,000 hospitalizations potentially averted.”
This move has not gone without criticism, but the CDC is following the same techniques that it uses to decide flu vaccine updates every year. There’s no real reason to think the safety profile of the BA.1 and BA.5 variant vaccine would be different. Furthermore, in terms of side effects, the bivalent vaccines have been pretty similar when compared to the original boosters:
In short, yeah, most people feel short-term side effects as a result of the vaccine. Your arm will probably hurt. You are probably going to feel tired, and your joints might be achy for a bit. But that tends to rapidly heal. Within 24 hours of my shot, I was up and headed to the Jazz’s scrimmage at Vivint Arena on Saturday — and going full celebratory bore for RSL’s 3-1 playoff-clinching win against Portland on Sunday.
What about rarer, but more serious, side effects? Data continues to look good on those. For example, myocarditis risk got a lot of publicity early in the COVID vaccine’s life span, but the evidence is clear now: Myocarditis happened about 11 times more frequently in people who actually got COVID than in people who were vaccinated.
But will enough people get the shot?
The unpredictability of the real world can complicate things in multiple ways. Not only is COVID’s scourge unpredictable this winter, so too is the number of people who will choose to get the vaccine. Only about half the people who received the primary series of vaccines chose to get a booster. Will more people get this one?
It’s fair to say that the 4% vaccine opt-in so far estimated by The Washington Post has significantly fallen short of projections. To see how much that matters, the Commonwealth Fund studied how vaccine uptake in three scenarios would impact U.S. lives and the federal budget. (Three is the perfect number of scenarios, scientists say.)
• Baseline: The bivalent booster vaccination continues at its current, underperforming, daily rate.
• Scenario 1: As many people get the bivalent booster as got the flu shot in 2020; or about 50% of the population. The modeling also took into account the age of people who get the shot — more old folks get the flu shot than young people.
• Scenario 2: 80% of people eligible for the booster get boosted.
There’s a huge difference in hospitalizations and deaths in each of the three scenarios. Here are rolling seven-day averages for each scenario:
That’s about 16,000 hospitalizations and 1,200 deaths per day at its peak at our current pace of vaccination. That’s significantly less than the omicron peak last winter of about 3,000 deaths per day, but it’s also a lot of unnecessary death we can avoid.
How much in total? Well, Commonwealth Fund did the math:
In all, if there was a vaccination campaign that even got as many people who get the flu shot to get this bivalent shot, researchers estimate that 75,000 lives would be saved, 745,000 hospitalizations avoided, and about 20 million infections averted. Oh, and we’d save about $45 billion in medical costs, including about $15 billion to Medicare and Medicaid.
You can see why the bivalent shot was approved — and why it’s a big deal that more people get it. We’ll see if winter weather or an uptick in cases encourage more people to get the booster, but our current trajectory means a lot of unnecessary lives lost and money spent.
Andy Larsen is a data columnist for The Salt Lake Tribune. You can reach him at email@example.com.
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