Concerns over waning immunity have persuaded some countries to deploy extra vaccine doses. But, experts are still divided on whether to give further doses to fully vaccinated people or not. This week, the Biden administration announced that most Americans will be eligible to receive COVID-19 vaccine booster shots (a third dose) eight months after receiving their second dose of either the Pfizer-BioNTech or Moderna messenger RNA (mRNA) vaccinations. This recommendation comes after the Centers for Disease Control and Prevention (C.D.C) recently released three studies, providing evidence that booster shots of the Moderna and Pfizer-BioNTech may be needed in the coming months. The C.D.C. studies demonstrate that, while immunizations remain extremely effective in preventing hospitalizations and fatalities, the barrier they provide against viral infection has waned in recent months.
“Boosters are offered to people who got the full course of a vaccine and developed a good response initially, but it waned over time.”
Emily Landon, Assoc. Prof. at University of Chicago
Is Immunity from Vaccines Waning?
Inoculation remains a critical tool to fight off infection. Data suggests that the overall efficacy as defined by prevention of serious disease remains very high, but that levels of antibodies may decline.
Delta Variant Challenges:
The Delta variant is currently the most widely circulating strain of the COVID-19 virus in the U.S. and can cause more severe infections and spreads faster than the previous strains in unvaccinated people. The New York Times compiled early preliminary data from seven states, who keep the most detailed data, which suggested an increase in breakthrough infections and a small increase in hospitalizations among the vaccinated, with the arrival of the Delta variant. Nevertheless, the numbers are very low compared to those unvaccinated and make a strong case for the protection of the vaccines. Experts believe that decline in vaccine immunity, the lack of precautionary measures, or the advent of the extremely contagious Delta variant — or a mix of all three — is attributed to the fall in vaccine effectiveness.
“Vaccines have an effectiveness of roughly 55% against all infections, 80% against symptomatic infection, and 90% or higher against hospitalization.”
Ellie Murray, an epidemiologist at Boston University
When To Get a Booster Shot?
According to federal health officials, Americans who received the Moderna or Pfizer-BioNTech vaccines should get a booster shot eight months after their second dose. It is still too early to determine the need for boosters for the Johnson and Johnson vaccine as it became available a few months later. The mRNA vaccine boosters plan to be available on Sept. 20 – based on approval by the Food and Drug Administration (F.D.A.)
Who’s Eligible for COVID Booster Shots?
The F.D.A. has already authorized booster shots for Pfizer-BioNTech and Moderna vaccines for people with weakened immune systems as well as those who fail to respond to the 2-vaccine dose (less than 3% of the population):
- People who’ve received solid organ transplants
- People with compromised immune systems
- Patients receiving cancer treatment for tumors
- People with advanced or untreated HIV
You May Need a COVID-19 Booster Shot
All vaccines are proven to be effective against the original variant of the coronavirus, SARS-CoV-2, and are expected to “strongly” boost protection against the Delta variant. While vaccinated people do get COVID-19 infections, they are far less common and less severe than among those who have not been vaccinated.
Therefore, vaccinated people need to consider receiving a booster shot, when eligible.