Photographer: Gabriela Bhaskar / Bloomberg
Photographer: Gabriela Bhaskar / Bloomberg
US public health advisers weigh recommendations for extend the interval between the first and second dose of Covid-19 vaccines, a potential strategy to quickly protect more people amid the spread of new variants.
A working group of the Immunization Practices Advisory Committee of the Centers for Disease Control and Prevention has discussed the idea, said a person familiar with the discussions. It has not yet been decided whether the full committee will take up the matter and provide official guidance, the person said. Jose Romero, chair of the committee and Arkansas health secretary, declined to comment because the deliberations are confidential.
US health officials have rejected a dose-escalation policy adopted by the UK that allows this until 12 weeks between Covid shots. Most drug manufacturers agree, saying the policy should follow the protocols used in testing the shots, with intervals set at three or four weeks. As dangerous variants threaten to ramp up US cases in the coming weeks, some states are asking what they can do to broaden protections.
“We know that until we have enough vaccine there must be a certain priority regulationClay Marsh, the czar of Covid-19 in West Virginia, said in an interview. “The next question is, is it better to put a single dose in the arms of more people?”
Possible strategy
President Joe Biden has ordered more vaccines Moderna Inc. and the partnership of Pfizer Inc. and BioNTech SE, which predicts there will be supplies to vaccinate 300 million Americans by the end of the summer. The strain could decline further in the coming weeks if a one-time vaccination comes out Johnson & Johnson is authorized, but immediate delivery is not expected to be great.
States are still trying to speed up immunizations, and West Virginia is among those pushing for the CDC and the Food and Drug Administration to provide more guidelines for dose stretching, according to the person in the know of the discussions. One possible strategy is to adhere to existing schedules for at-risk groups such as health workers and the elderly, while offering flexibility to younger people and those with less exposure to the virus.
Read More: Why Delaying Second Injection of Covid Vaccine Is Messy: QuickTake
The debate over the pause between shots – three weeks between Pfizer doses in company studies and four weeks between Moderna’s – has been heated. Proponents of longer intervals say that one dose provides at least some protection, while opponents argue that it is unclear how long that protection lasts or how much is even provided.
A notable exception is AstraZeneca Plc, whose Covid-19 injection is approved in the UK and dozens of other countries, although not in the US. Cambridge, UK-based Astra says its studies indicate a 12-week interval increases efficacy, and the World Health Organization recommended 8 to 12 weeks between doses when authorizing the injection last week.
Both the CDC and the FDA have moderate their stance on the matter. Shortly after Biden took office, the agencies said wait until six weeks between shots is acceptable in special circumstances.
Achieving a balance
In Illinois, the demands of getting second doses to humans are overwhelming for the state’s ability to administer the first. The number of second shots in the state are likely to surpass first doses until March, when allocations increase, the health department said in a statement Saturday.
“We have found this balance between promoting both the first and second doses,” director Ngozi Ezike said on Feb. 2 in a hearing of the US House of Representatives. “And we want to use as many available doses as quickly and effectively as possible.”
Photographer: Al Drago / Bloomberg
Anthony Fauci, Biden’s chief medical adviser, said last month that he is concerned about attempts to delay second shots.
“I would be concerned because you don’t get full efficacy until you get that second dose,” he said on January 25. World Economic Forum.
‘Push the Envelope’
There is also the potential that lower levels of protection afforded by one vaccine dose, compared to two, allow for faster spread of variants to gain a foothold, Jesse Goodman, former chief scientist at the FDA, said in an interview. A two-dose regimen with reduced efficacy against a mutant in a single dose might not be effective against the same strain, Goodman said.
A longer interval with a single dose on board means “extending the period when people are more at risk of getting infected,” he said. “I have personally seen and heard about numbers of people who are already getting Covid after the first dose.”
According to Marsh, Covid’s czaar, West Virginia will not take steps without a green light from federal officials, but he is looking at countries like the UK and Israel where leaders are giving as many first doses as possible.
“Our strategy for Covid must constantly balance what our national experts are saying,” he said, “but it is also our responsibility to our citizens to ensure that we are constantly trying to push the envelope.”