New Haven Register (New Haven, CT)
Immunity may last year or more
Yale doc: Vaccine could protect as long as 3 years; studies planned for younger children
NEW HAVEN — Immunity provided by the Pfizer COVID-19 vaccine appears to last for at least a year and possibly longer, doctors at Yale New Haven Health said Wednesday.
Dr. Onyema Ogbuagu, the principal investigator who has led the clinical trials of the Pfizer-BioNTech vaccine at the Yale Center for Clinical Investigation,
said “the early signals suggest that it should last longer than a year, assuming no new variants that evade the vaccine-induced responses.”
“We don’t have all the answers yet,” he said, but, “we think, based on the trajectory, that it should provide protection for a year or even longer … possibly two or three.”
He said he based his projection on
participants in the first Pfizer clinical trial, which began about a year ago, as well as on the immune response of patients who recovered from COVID-19. He said patients who had SARS, another respiratory disease caused by a coronavirus, “showed immunologic memory” as much as 17 years later.
Dr. Thomas Balcezak, chief clinical officer at Yale New Haven Health, said at an online media briefing, “We’re all on the edge of our seat to see” how long immunity will last from vaccines, Balcezak said.
“The people who were enrolled in the clinical trials are going to be followed for a period of years,” he said. “Many of those individuals were vaccinated just about a year ago this month, and so far it indicates that they still have immunity. … Right now it looks like at least a year for that immunity.”
A clinical trial of the Pfizer vaccine was completed on children 12 to 15 years old in January, Ogbuagu said, “and we’re putting through a protocol now that would let us do kids” from 5 to 11 years old. He said that study likely would start in May or June. He did not know how many participants would be enrolled.
Since the success of the vaccine depends on whether participants get COVID, there is no timeline to end the study of 12- to 15-yearolds, but “anecdotally, the kids tolerated the vaccines well,” Ogbuagu said. He said researchers also will be able to measure the “immune response generated by the vaccine,” but there were no results to report yet.
Ogbuagu said it also appears that vaccinated people will not develop asymptomatic infections that could spread the disease.
“We’re starting to have more data suggesting the vaccine does have significant protection,” he said. In a study in Israel, there was 94 percent protection from transmission, he said. “We think that the vaccines protect against having symptoms, but they also protect against transmission robustly,” Ogbuagu said.
According to the Centers for Disease Control and Prevention’s website, “We’re still learning how well COVID-19 vaccines keep people from spreading the disease. Early data show that the vaccines may help keep people from spreading COVID-19, but we are learning more as more people get vaccinated.”
The CDC also states, “We’re still learning how long COVID-19 vaccines can protect people.”
Anthony Lupinacci, marketing director for the Shubert Theater, was a part of Pfizer’s Phase 3 trial, but didn’t get his first injection until August 2020. Later, Pfizer decided to unblind the study and “I found out I had received the placebo,” he said. He was then scheduled to receive the vaccine and received his second dose March 10.
“I completely commend what Pfizer has done,” Lupinacci said. “The professionalism with which they handled it is amazing.”
Ogbuagu said Yale has been selected as a site for a clinical trial of the Moderna vaccine for children from 6 months to 11 years old, but said it is too early to say how that will proceed. “We have to put a protocol through regulatory processes,” he said. “It’s not unusual that we get selected for a site, then a snag happens along the way.”
Balcezak said that, while there are concerns in Europe about the AstraZeneca vaccine causing blood clots, “so far, AstraZeneca has not applied for emergency use authorization in the United States. … My bet is by the time AstraZeneca looks to see an [emergency use authorization] in the United States we will be most of the way there in getting our population vaccinated.”
Balcezak the approved vaccines appear to be reducing the number of COVID cases in older people. “We’ve seen a sharp reduction in the hospitalization rate of those over the age of 75,” he said. “And as we continue to vaccinate all populations, I anticipate we will see that drop in those age groups, as well.”
But he added, “I really do think that complacency could be our enemy here. We’re all focused on getting vaccinated. We’re all focused on what is going to happen as we continue to open up. But I think that just adhere to those same public health risk factors and pay attention to masking and distancing and, by all means, the safest thing to do is hold these events outside … which is very, very safe.”
Yale New Haven Health CEO Marna Borgstrom reported Wednesday that there were 165 COVID-19 patients in the system’s five hospitals, “and only 44 of those patients are in intensive care units and a little fewer than half of those are on ventilators.” That is down from 447 on Dec. 8.
There were 97 patients at Yale New Haven Hospital, 43 at Bridgeport Hospital, 11 each at Greenwich and at Lawrence and Memorial hospitals and two at Westerly Hospital in Rhode Island.
She said the number of admissions of patients 75 and older has declined “for four straight weeks.”
Balcezak said Yale New Haven has given more than 160,000 doses of vaccine, with more than 100,000 people fully vaccinated. He said they have been vaccinating up to 12,000 people per week, limited by the allocation of doses from the state.