Can we get a second bivalent booster?
Vaccines continue to be the most important tool in our arsenal to avoid severe illness and death from COVID-19. In the US, we have gotten used to COVID-19 boosters being recommended to us regularly around the calendar to keep our immunity levels up. Thus, people who got the bivalent booster when it was first available in September may be wondering if they should get another, since it’s been six months.
Currently, the US seems to be pivoting toward a single, annual booster shot strategy. President Biden advocated for this strategy in September, 2022and the CDC Advisory Committee on Immunization Practices (ACIP) discussed this strategy at their February 2023 meeting.
Pros of annual boosting
The many booster recommendations over the past couple of years have been confusing to the public and, as a result, every subsequent booster has had a poorer uptake rate. Currently, only 16% of eligible people and only 41% of those over 65 in the US have gotten the newest bivalent booster shot, the most recent one specifically targeting the Omicron variant. The annual booster strategy would help simplify messaging around when to get a booster. People are already in the habit of getting an annual influenza vaccine in the fall, so the COVID-19 booster could be done at the same time. Another point in favor of the annual strategy is that most Americans have either been vaccinated, have had one or more COVID-19 infections or both, so we do have a level of population immunity to COVID-19. Additionally, while SARS-COV-2 continues to evolve, the latest variants circulating in 2022-23 have not led to population level surges in hospitalization.
Cons of annual boosting
While once-a-year boosting may be acceptable for most Americans, given the reasons stated above, there is not yet enough data for people in high risk / vulnerable groups to be 100% comfortable with once-a-year boosting. We know that age, time since last dose, a person’s immune status and the incidence rates of COVID-19 circulating at the time all affect the vaccine’s effectiveness. Rates of severe illness and death are higher in older people and those with chronic health conditions. Surges have occurred in winter months (which is accounted for in the annual strategy), but surges have also occurred due to escape variants at other times of the year, to which the older, immunocompromised, and chronically ill will be more susceptible.
So, what should you do?
While good arguments can be made in support of the annual shot strategy for most Americans, we do not really know whether this will be enough protection for everyone given waning mRNA vaccine effectiveness over time and the unpredictability of viral mutations. My recommendation is that people older than 50, those with chronic health conditions, and those who are immunocompromised may want to have a conversation with their health care provider about possibly getting vaccinated more frequently.