Are Mix-and-Match Booster Shots Right For Seniors?

The Centers for Disease Control (CDC) just announced its recommendation for Covid-19 booster shots. The groups who were eligible soonest for the original vaccine are now urged to get a third (or second) shot to supplement and reinforce their fully vaccinated status. The United States’ vaccination level has stalled compared to many other countries with ample supply of vaccines, as less than sixty percent of the population is fully vaccinated. Vaccinating the remaining forty percent is an important goal, but so is boosting the antibody levels of frontline workers, the immunocompromised and seniors. We answer four questions about mix-and-match booster shots for seniors and caregivers in San Diego.

The CDC announced on October 21st that several groups of people, including frontline workers, long-term care residents, people with underlying conditions, and seniors over age 65, were eligible to receive a Covid-19 vaccine booster shot. Further, these eligible individuals were free to choose any manufacturer’s booster dose, which the CDC calls a ‘mix-and-match’ approach. This means that seniors and those receiving in home care in San Diego now have to decide if they need a booster shot, when they should get it, and which one they should choose. Here are the answers to the most pressing who, what, when and which questions.

Who Is Eligible for a Covid-19 Booster Shot?

The CDC recommends booster shots for the following:

  • “People
    • 65 years and older,
    • 50–64 years with underlying medical conditions, or
    • 18 years and older who live in long-term care settings should receive a booster shot.
  • People 18 years and older should receive a booster shot at least 2 months after receiving their Johnson & Johnson/Janssen COVID-19 vaccine.”

When Should You Get a Covid-19 Booster Shot?

According to the CDC’s recommendations:

  • If you received two doses of the Pfizer-BioNTech or Moderna vaccine,
    • You can get a booster shot at least 6 months after your second shot
    • You can get any of the COVID-19 vaccines authorized in the United States
  • If you received the one-dose Johnson & Johnson’s Janssen vaccine
    • You can get a booster at least 2 months after your second shot
    • You can get any of the COVID-19 vaccines authorized in the United States

Why Should You Get a Covid-19 Booster Shot?

The data shows that antibody levels and protection from hospitalization and severe illness drop in the immunocompromised and people over age 65 just months after the last dose of the vaccine. And BusinessInsider.com reports that those “who have received Johnson & Johnson’s vaccine could likely all benefit from a booster shot (at least two months after their initial vaccine), regardless of their age or immune status. Though they are a small fraction of the fully vaccinated in the US (8%), real-world data is showing they are at risk. J&J’s single-shot vaccine is clearly not protecting them from hospitalization and death as well as the two-shot mRNA vaccines.” The same data shows that people under age 65 with no underlying conditions or immune issues don’t need a booster shot, as antibody levels and protection from hospitalization and severe illness remain high after many months.

Which Covid-19 Booster Shot Should You Choose?

According to the LA Times, Covid-19 vaccines can be mixed with the following results:

  • The Pfizer two-dose + Moderna booster produces antibody levels 32 times higher than the levels measured just before the booster
  • The Pfizer two-dose + Pfizer booster produces antibody levels 20 times higher than the levels measured just before the booster
  • The Pfizer two-dose + Johnson & Johnson booster produces antibody levels 13 times higher than the levels measured just before the booster
  • The Moderna two-dose + Moderna booster produces antibody levels 10 times higher than the levels measured just before the booster
  • The Moderna two-dose + Pfizer booster produces antibody levels 11 times higher than the levels measured just before the booster
  • The Moderna two-dose + Johnson & Johnson booster produces antibody levels six times higher than the levels measured just before the booster
  • If you received the one-dose Johnson & Johnson vaccine, the recommended booster is definitely an mRNA vaccine. The data shows no obvious advantage at this point between the Pfizer or the Moderna shot in this case.

In October 2021, the unvaccinated accounted for a large majority of San Diego’s positive Covid-19 cases, hospitalizations and deaths. However, the rate of new Covid-19 cases in the vaccinated grew slightly in the first weeks of the month. This could represent a decrease in immunity and protection from the vaccine, a relaxation of self-protective measures, or both. The approaching holidays will offer a lot of temptation to socialize with friends and family, but we need to continue to observe safety protocols as much as possible. The vaccine and the booster don’t prevent infection, and the pandemic is not over.