Real-World Vaccine Data Shows Promise as Eligibility Expands

As more states open up Covid-19 vaccine eligibility, the first data from the general population shows only a slight decrease from astounding effectiveness observed in clinical trials.

Dr. Rochelle Walensky, director of the Centers for Disease Control and Prevention, leads President Joe Biden into the room for a Covid-19 briefing at the headquarters for the CDC Atlanta on March 19. (AP Photo/Patrick Semansky)

(CN) — Demonstrating how results from the lab hold up in real-world settings, the Centers for Disease Control and Prevention released new data Monday on Covid-19 vaccine efficacy. 

The results focused primarily on the Pfizer and Moderna vaccines, both in use since December 2020, finding that each was 90% effective after both doses. The number is a slight bump down from the 95% reported during vaccine trials. 

“This is very reassuring news,” said CDC epidemiologist Mark Thompson, lead author of the study. “We have a vaccine that’s working very well.”

Nearly 4,000 health care workers, first responders and other essential workers completed coronavirus testing for 13 weeks to produce the first real-world efficacy data. 

Studying how the vaccine plays out in communities is important because effects can vary once a vaccine or drug is broadened from participants in controlled experiments to the general public. 

Pfizer and Moderna’s vaccines are both based on new vaccine technology that uses messenger RNA. Other vaccines, like Johnson & Johnson’s, instead use a weakened virus to trigger the production of antibodies. 

While J&J’s vaccine, which has a 72% efficacy, is given in a single shot, both of the mRNA-based vaccines require two doses. As for partial immunization from Pfizer and Moderna — measured more than 14 days after the first dose, but before the second — the new CDC data shows 80% effective. 

Participants in the study were 2,500 who got both doses; 500 who got just one dose; and 1,000 people who did not get vaccinated. Each individual took nasal swabs over the course of the study to track their chances of getting infected with the coronavirus.  

Of 205 infections, 161 were in the unvaccinated group, the researchers found. Of the 44 people who still got infected after getting a vaccine, 33 of them were infected within two weeks of their last shot, meaning before the point they were considered fully vaccinated. 

Only two people involved in the study were hospitalized, though CDC researchers did not disclose whether those people had been vaccinated. 

The study was conducted in Miami; Salt Lake City; Portland, Oregon; Temple, Texas; Duluth, Minnesota; and Phoenix, among other areas of Arizona, including Tucson. 

“These findings should offer hope to the millions of Americans receiving COVID-19 vaccines each day and to those who will have the opportunity to roll up their sleeves and get vaccinated in the weeks ahead,” CDC Director Dr. Rochelle Walensky said in a statement. “The authorized vaccines are the key tool that will help bring an end to this devastating pandemic.”

Across the country, more than 28% of Americans have received at least one dose of Covid-19 vaccine, and nearly 16% are fully vaccinated, according to CDC data. 

The CDC recommends Covid-19 vaccination for all who are eligible — a category that is set to expand soon in all 50 states. 

Last week, California and Florida announced that all adults will be eligible for a vaccine ahead of the May 1 deadline set by President Joe Biden. 

On Monday, New York became the latest state to set its adult eligibility date, after Governor Andrew Cuomo tweeted saying people ages 16 and up will be eligible on April 6. 

Cuomo previously held off on setting a date, saying he wanted to wait until federally controlled vaccine supplies were more certain. 

“I don’t want to say we’re going to open up to 30 year olds in three weeks and then something happens with the allocation,” Cuomo said last week, noting that “a lot of this is out of our control.” 

“I’d rather get the specific allocation number and then tell the people of the state so we don’t have to change advice, and we don’t create pandemonium for the scheduling operation,” Cuomo said. 

Reversing that take on Monday, Cuomo said all New Yorkers over age 30 will be eligible starting Tuesday, with the remainder of adults becoming eligible in just over a week.

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