Province recommends boosters for health-care workers, people immunized with AZ, Janssen vaccines

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Manitoba health-care workers and people fully vaccinated against COVID-19 with either AstraZeneca or the single-dose Janssen vaccine are eligible for a booster shot of an mRNA vaccine.

Dr. Joss Reimer, medical lead for the COVID-19 vaccine task force, said a third dose of either the Pfizer or Moderna vaccine is recommended for health-care workers who have direct contact with patients, residents and clients at hospitals, clinics, personal care homes and elsewhere.

There are approximately 50,000 health-care workers in the province, the task force said.

Reimer said getting the third dose is voluntary, and the province will not change its definition of what it means to be fully vaccinated.

“This came from discussions with Shared Health and concerns that they had around what might happen in the fourth wave, particularly if staff were to become ill, even with mild infections,” Reimer said Wednesday.

The National Advisory Committee on Immunization has not yet recommended booster shots for health-care workers.

In a statement to the Free Press, a Health Canada spokesperson said provinces and territories can offer an additional vaccine dose to specific populations “to enhance their protection against COVID-19.”

“This would be considered off-label use since Health Canada has not authorized a three-dose regimen for any of the vaccines authorized in Canada,” the statement said.

Previously, the federal advisory committee has recommended third shots for people with immunocompromising conditions, residents of personal care homes and seniors who live in congregate settings.

In Manitoba, third shots will be offered to all eligible health care workers regardless of age and should be administered at least six months after the second shot.

“As we’ve seen to the west, some of the strains that have occurred with the fourth wave, and as we’ve experienced in the third wave, it was important for Shared Health to use every single tool available to them to improve the health-care capacity to be able to provide services to Manitobans,” Reimer said.

She added most fully vaccinated health-care workers are not at risk of a severe outcome if they become infected with COVID-19.

However, public health has noted “somewhat higher rates” of breakthrough COVID-19 infections in health-care workers compared with the general population, possibly due to increased exposures as they care for people who are known to be infectious, Reimer said.

The province estimates about 6,700 Manitobans have received either two doses of the AstraZeneca or Janssen (Johnson & Johnson) vaccines and are eligible for a third shot.

Reimer said the best evidence to support a booster shot for AstraZeneca recipients comes from a study in the United Kingdom.

The 20-week study showed a drop in protection against mild infection in healthy individuals who received two doses of AstraZeneca and a small but significant drop in protection against severe outcomes for healthy people, Reimer said.

People who meet the criteria for a third dose can get a shot of either Pfizer or Moderna at any location that offers COVID-19 vaccines.

“This is not urgent the way dose 1 and dose 2 were. People who have had two doses have protection,” Reimer said. “We have seen that some people have lower levels over time, but most people are still well protected.

“We’re not saying that health-care workers or people who received two doses of AstraZeneca should drop everything and get their dose tomorrow. This is really something that people can do over the next weeks as they get further and further away from their second dose.”

Reimer said Manitobans who received a mixed vaccination series that included AstraZeneca and either Pfizer or Moderna are not being considered for third doses at this time.

“The immune response in other studies when you get a mixture of mRNA with a viral vector was very high and at least as high as getting two mRNA doses,” Reimer said. “We have no reason to believe that people with a mixed dose would end up similar to those who have two doses of AstraZeneca.”

Her team is looking at expanding eligibility for third doses to people based on age and to people in congregate living settings, and it is possible that third doses will be recommended more broadly in the coming months.

“Based on what we’re seeing so far, there’s a good chance that we’ll recommend a third dose for most people this calendar year, but I don’t want people to be worried that they’re not well protected,” Reimer said.

“The studies have shown that when we’re talking about hospitalization and death, these vaccines are extremely effective and that that protection lasts for a long time.”

danielle.dasilva@freepress.mb.ca