The booster confusion in emails I have received over the past week is palpable. Should I get a spring booster?

This is how I’m thinking about it. Hopefully it helps.

Level of urgency

The level of urgency for a spring booster should be dependent on two things:

1. Risk factors. Ninety percent of people in the hospital “for” or “with” COVID-19 do not have a bivalent vaccine (i.e. fall booster). This group has the highest level of urgency.

If you had the fall booster, you’re in pretty good shape against acute severe disease. Will this change with time? We don’t know. The U.S. (and a handful of other countries) don’t want to risk finding out, so a spring booster is “permissible”.

People in the hospital today for COVID-19 are older adults and/or those with a comorbidity. (If you want to know why, read more here.) This means groups with the second highest level of urgency for a spring booster are those with a fall booster and:

• Adults over 75 years;
• Adults over the age of 65 years with a comorbidity; and,
• Moderate or severely immunocompromised.

If you’re not in one of these groups, your level of urgency is significantly reduced. You could time a booster for maximum protection. If I were over 65 without a comorbidity, I would, especially since wastewater concentration is nosediving. For example, four weeks before a really big event you don’t want to miss, like a wedding, get a booster. Or wait to get a booster on the chance that another variant of concern comes (and get it right before a wave).

2. Timing. If you’re in one of the urgent groups, the next question is: When was your last infection or vaccine?

• 6+ months ago: Go get a spring booster today.
• 4-6 months: Schedule one, but you don’t need to rush to the pharmacy.
• <4 months: Wait. But do not wait until past May/June, so that you enough runway time before the (anticipated) fall vaccine.

Potential individual-level risks

People are wondering about risks of spring boosters. The risks are small, especially when we compare them to risks resulting from infection. Perhaps the following risks should really only be considered for those who are not in the high-urgency groups above.

• Myocarditis. This is the biggest risk of COVID-19 vaccines but is really only a problem for adolescents. (Benefits still outweigh risks. There is also a risk of myocarditis from COVID-19 infection.)
• Flu vaccine. There may be an increased risk of stroke if you get flu and COVID-19 vaccines at the same time. This shouldn’t be a problem for your spring decision.
• Side effects. Some people get their butt kicked from side effects immediately after the vaccine. Some just don’t have the ability to be out of commission for a few days.
• Imprinting. We know imprinting is a thing with COVID-19. And, we should expect imprinting. (Read a deep dive here.) The biggest influence of imprinting occurs after first exposure to the virus (through vaccine or infection). We still don’t have good evidence that imprinting is harming protection, though.
• Unknown unknowns. We simply don’t know the risks of stimulating the immune system with 6 shots in 2 years, too. There are always unknown risks, albeit small.

Bottom line

Anyone who hasn’t had a bivalent vaccine (i.e. fall Omicron booster) needs to get one. If you have your bivalent already, there is a spectrum of urgency. Try not to overthink it too much.

Love, YLE

“Your Local Epidemiologist (YLE)” is written by Dr. Katelyn Jetelina, MPH PhD—an epidemiologist, data scientist, wife. During the day she works at a nonpartisan health policy think tank and is a senior scientific consultant to a number of organizations, including the CDC. At night she writes this newsletter. Her main goal is to “translate” the ever-evolving public health science so that people will be well equipped to make evidence-based decisions. This newsletter is free thanks to the generous support of fellow YLE community members. To support this effort, subscribe below. (Reprinted with permission)