Scientists at the National Advisory Committee on Immunization are reviewing research that suggests people who have been infected with COVID-19 can turbocharge their antibodies with just one dose of a vaccine.
The committee is “actively reviewing evidence on the protection offered by one dose for those previously infected, and whether a second dose continues to be necessary,” says a statement from the panel.
Caroline Quach-Thanh said the committee is “debating” the question of how many vaccine doses someone who has been infected with COVID-19 requires.
“France and Quebec have said only one,” said Quach-Thanh, chair of the committee, in an email.
Studies have suggested people who have had COVID-19 may produce the required antibody response with just one dose of a vaccine.
A letter in the New England Journal of Medicine earlier this month says the question of whether one dose is enough “requires investigation.” It’s written by 32 researchers from the Icahn School of Medicine at Mount Sinai in New York after conducting a small study.
It suggests people who have been infected with the novel coronavirus may produce 10 to 45 times as many antibodies after the first dose of the Pfizer-BioNTech or Moderna vaccines compared with someone who hasn’t had COVID-19. The research is yet to be peer-reviewed.
Quach-Thanh said data shows that the response to the first dose of vaccine is strong for those who have been infected with the virus.
“Like a booster dose,” she said.
Those who have been infected and get a second shot may also have stronger side-effects, such as fever, aches and feeling tired, which are signs their immune system is already primed, Quach-Thanh said.
“The question that remains is: is that true for everyone or at least for the vast majority?”
Dr. Bonnie Henry, British Columbia’s provincial health officer, said early data from around the world suggest people who have had a lab-confirmed positive test for COVID-19 get a good response from just one dose of a vaccine.
“The jury is still out but more and more it is looking like they get a really strong booster effect from a single dose and a second booster may not be necessary,” she said.
Quebec’s public health director, Horacio Arruda, told a news conference earlier this week that immunization experts believe a single dose of vaccine, when given three months after recovery from the disease, provides the same amount of immunity as two doses.
A second dose, Arruda explained, is not recommended for people who have had COVID-19 because “it doesn’t give more immunity, and it brings more significant adverse effects,” such as flu-like symptoms.
Prof. Fiona Brinkman of Simon Fraser University’s molecular biology and biochemistry department said the number of antibodies produced by a person may depend on how severe their COVID-19 infection was.
That does not mean people need to get an antibody test done before getting a vaccine, although that may change, she added.
“Right now, the policy is that we’re just vaccinating everybody and doing that first dose.”
However, Quach-Thanh warned that the presence of antibodies is not, in itself, a sign of protection and they are all not created equal.
“Some people without much antibodies will have protection, while others with antibodies may not be that well protected,” she said.
Brinkman said it’s also possible that there may be a difference in the kind of antibodies produced after a COVID-19 infection and a vaccine.
“The most important thing is to have these certain antibodies — what we call neutralizing antibodies — that we really want,” she said, adding the vaccines have been shown to produce them.
The experts said there is no harm in those who have been infected with COVID-19 getting both shots.
The statement from the committee said it is also evaluating how long someone previously infected with COVID-19 could wait before getting a vaccine, based on emerging evidence.
Brinkman said one of the concerns researchers have is how long immunity might last.
“This disease literally hasn’t been around long enough to allow us to appropriately assess how long you have antibodies and an immune response that will be effective against this virus, if you’ve either been vaccinated or you’ve had the disease.”
Researchers said it could also potentially mean that the vaccine can be delivered into arms faster because a number of people may only need one dose of the shot.
“It really is good news,” Brinkman said. “If anything, it’s a good thing.”
COVID cases in Ontario could spike to 30,000 per day by June
TORONTO (Reuters) – New cases of COVID-19 in Canada‘s most populous province could rise more than six fold, topping 30,000 per day by early June if public health measures are weak and vaccination rates remain flat, a panel of experts advising the province of Ontario said on Friday.
Even if measures to control the virus are “moderate,” the number of patients in Ontario ICUs could reach 2,000 in May, up from 695 on Friday.
The College of Physicians and Surgeons of Ontario told doctors last week they may soon have to decide who can and cannot receive intensive care.
(Reporting by Allison Martell; Editing by Chris Reese)
Moderna sees shortfall in Britain COVID vaccine shipments, EU deliveries on track
ZURICH (Reuters) – U.S. drugmaker Moderna expects a shortfall in COVID-19 vaccine doses from its European supply chain hitting second-quarter delivery quantities for Britain and Canada, though European Union– and Swiss-bound shipments are on track, a spokesperson said.
The delays, first announced on Friday when Canada said Moderna would be delivering only about half the planned 1.2 million doses by the end of April, come as Switzerland’s Lonza ramps up three new production lines to make active ingredients for Moderna vaccine supplies outside of the United States.
“The trajectory of vaccine manufacturing ramp-up is not linear, and despite best efforts, there is a shortfall in previously estimated doses from the European supply chain,” Moderna said in a statement.
Lonza didn’t immediately return a phone call and email seeking comment on any issues in its production.
(Reporting by John Miller; editing by David Evans)
Moderna says vaccines to Canada to be delayed due to Europe shortfall
(Reuters) -Moderna Inc said on Friday a shortfall in COVID-19 vaccine doses from its European supply chain will lead to a delay in deliveries to some countries including Canada.
She said one to two million doses of the 12.3 million doses scheduled for delivery by Moderna in the second quarter would be delayed until the third.
Moderna officials in Europe did not immediately comment on the reason for the delays or give the total number of countries that would be impacted.
“Vaccine manufacturing is a highly complex process and a number of elements, including human and material resources have factored into this volatility,” said Patricia Gauthier, an executive at Moderna Canada.
Canada has distributed a total of 2.82 million doses of the Moderna vaccine as of April 14 and 12.7 million doses of COVID-19 vaccines in total.
Moderna has been aiming to deliver 700 million to 1 billion doses of the COVID-19 globally this year, including from plants in Europe and the United States.
Swiss contract drug manufacturer Lonza makes active ingredients for Moderna’s vaccine in Visp, but it was still ramping up three new production lines that once operational would be able to produce 300 million shots annually.
The current supply, demand and distribution landscape has led the drugmaker to make adjustments in the expected second-quarter deliveries, Gauthier said.
(Reporting by Manas Mishra in Bengaluru, Allison Martell in Toronto and John Miller in Zurich; Editing by Arun Koyyur)