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How Quickly Will Boosters Provide Holiday Protection?

November 22, 2021

It’s the first full week for COVID-19 boosters available for Americans at least 18 years old, but it’s likely too late to offer additional protection for Thanksgiving.

“It does take time for your immune system to ramp up,” said Dr. Ulysses Wu, Hartford HealthCare’s System Director of Infection Disease and Chief Epidemiologist. “So, with regards to people traveling for Thanksgiving, it’s going to have no impact. But for the holidays after that, it’s definitely going to have some impact.”

Researchers from Israel and the United States, in a study of 728,321 people who received a third dose of the Pfizer-BioNTech vaccine between July 2020 and September 2021, estimate a booster’s effectiveness would start after seven days. The Food and Drug Administration and the Centers for Disease Control and Prevention last Friday authorized both COVID-19 boosters from both Pfizer-BioNTech and Moderna for all American adults previously vaccinated.

Connecticut ranks first nationally with 84 percent of adults vaccinated, Gov. Ned Lamont said during a Monday afternoon media briefing, and ninth with18 percent of those eligible having received a booster. Yet the state’s, and the Northeast’s, COVID-positive rate continues to trend upward. Connecticut’s 3.53 percent positivity rate Monday, and 3.3 percent over the past seven days, represent highs since September.

“We’re much better prepared than we were a year ago,” Lamont said, “much better than prepared than we’ve been. You’ve got the vaccine. You’ve got the boosters. You’ve got the masks. We’re going to get through this No question about it. Let’s make sure that the next wave is the most mild of all.

As Thanksgiving week begins, here are New England’s test-positivity rates reported by Johns Hopkins University:

  • Massachusetts: 3 percent.
  • Connecticut: 3.4 percent.
  • Vermont: 3.4 percent.
  • Rhode Island: 3.8 percent.
  • Maine: 6.9 percent.
  • New Hampshire: 10.8 percent.

Others:

  • New York: 3.8 percent.
  • New Jersey: 21.3 percent.
  • Pennsylvania: 13.6 percent.

The boosters were endorsed only days after a study of nearly 800,000 veterans found a dramatic drop in effectiveness in all three available vaccines.

Here are tests results provided by researchers from the Public Health Institute in Oakland, the Veterans Affairs Medical Center in San Francisco and the University of Texas Health Science Center:

  • Moderna: 89 percent effective in March, 58 percent effective in September.
  • Pfizer-BioNTech: 87 percent effective in March, 45 percent effective in September.
  • Johnson & Johnson: 86 percent effective in March, 13 percent effective in September.