View Israeli UK study informing of second delay in administration of BC

She and health minister Adrian Dix said in a joint statement Wednesday that the goal is to protect as many people as possible through available vaccines as soon as possible.

“A second booster dose of 16 weeks can increase the number of people who have access to these safe and effective vaccines, providing more durable and longer lasting protection. It’s possible, “the statement said.

Newfoundland and Labrador also announced a four-month interval, with a statement on Wednesday recommending a 16-week dosing interval if supply is limited, Canada’s National Advisory Board on Immunization. Was announced.

Dr. Bonnie Henry fends off criticism of BC’s decision to postpone the second dose of the COVID-19 vaccine and tells the public that she is “very confident” in her plans to be based on science and data. I am. 3:53

A single dose of the Pfizer-BioNTech vaccine reduces the number of asymptomatic COVID-19 infections by 75 times, although not yet peer-reviewed in a study published February 24 by a team at the University of Cambridge in the United Kingdom. It is suggested that you can do%.

Over the two weeks of January, the team investigated the results of thousands of COVID-19 tests from unvaccinated and vaccinated medical staff who showed no signs of infection in a university hospital.

The study found that 26 of the 3,252 tests by unvaccinated workers, or 0.8%, were positive. By comparison, 13 of the 3,535 tests from vaccinated staff (0.37%) were positive within 12 days of vaccination and 1,989 tests from vaccinated workers. Four of them (0.2%) were positive 12 days or more after the shot. ..

1/4 reduction in risk

The findings suggest that healthcare workers vaccinated more than 12 days ago have a one-quarter reduction in the risk of asymptomatic COVID-19 infection, or 75% protection.

“This is great news. The Pfizer vaccine not only helps prevent SARS-CoV-2 disease, but also prevents infection and reduces the chance of the virus being transmitted to others,” said research leader Mike Weeks. The doctor says. Statement by an infectious disease specialist at the University of Cambridge.

Henry states that the situation in BC, where vaccine supply is limited and the virus continues to spread, is similar to that in the United Kingdom. The UK recommends prioritizing the first dose of the Pfizer-BioNTech and Oxford-AstraZeneca vaccines over the second dose.

The UK Vaccination and Vaccination Joint Committee said in December that a second dose of either vaccine could be given up to 12 weeks after the first dose.

Another recent study in the United Kingdom concluded that the Oxford-AstraZeneca vaccine was more effective when the second dose was given later. According to the study, published in the peer-reviewed medical journal The Lancet on February 19, the vaccine was 81% effective with a second dose 3 months after the first dose and 55% after 6 weeks. there is.

In Israel, researchers studied the effects of a single dose of the Pfizer-BioNTech vaccine and published the results at The Lancet on February 18, determining that it was 85% effective against symptomatic COVID-19 infection. did.

Data from 7,214 healthcare professionals

The authors of the study analyzed data from 7,214 health care workers vaccinated at the Sheva Medical Center, Israel’s largest hospital. They found a 85% reduction in symptomatological infections between 15 and 28 days after the first dose.

Henry also pointed out a study conducted in Quebec. Authorities said it would extend the gap between two doses in January up to 90 days.

The Quebec National Institute of Public Health stated on February 18 that the first dose of Pfizer-BioNTech and Moderna vaccines was approximately 80% effective 14-28 days after injection.

As part of this, manufacturers provide different guidelines for the time between doses. Pfizer-BioNTech recommends 3 weeks, Moderna 4 weeks, Oxford-AstraZeneca 8-12 weeks.

But it must not be the company that determines the appropriate intervals, said Dr. Danuta Skowronski, epidemiological leader at the Centers for Disease Control and Prevention in British Columbia.

“You shouldn’t ask manufacturers for their blessings in doing this. It’s not their role,” she said.

“It is really the responsibility of the public health authorities to do that full benefit / risk analysis for their population.”

92% valid

Henry states that manufacturers have completed clinical trials according to a short timeline in order to bring the vaccine to market as soon as possible.

Skowronski has supported BC-based studies supporting the state’s plans, including the finding that the first dose of Pfizer-BioNTech and Moderna vaccines reduces the risk of COVID-19 for caregivers and healthcare workers by up to 90 per person. I took the lead. Cent.

She also considered submitting Pfizer-BioNTech to the US Food and Drug Administration and found that it underestimated the effectiveness of its own initial dose. The manufacturer said it was 52 percent effective, but it included data from the first two weeks of the shot, which is the time when the vaccine is generally ineffective.

When Skowronski cut out the data for the first two weeks, she found it to be 92% as effective as the first dose of the modelna vaccine.

BC reported 542 new COVID-19 cases and 7 new deaths on Wednesday, bringing the total number of deaths associated with the virus to 1,372 in the state. He added that there are 18 new cases of the subspecies of concern, for a total of 200 cases.

Less likely to be infected

Horacio Bach, an adjunct professor of infectious diseases at the University of British Columbia, said the state had ample evidence to support a four-month interval, but it wasn’t until he announced such a long delay between doses. He believes it is the first time in the world.

He said the people who received the first shot now have antibody reserves four months later. He said people would still have enough antibodies to prevent serious illness and hospitalization, even if four months were too long to wait.

“I don’t think four months is ready to go out of the box,” he said. “We can wait for a decent period.”

Bach pointed out, for example, that hepatitis B vaccine booster would be given one year later.

He added that giving as many first shots as possible would help prevent the transmission of the disease in the state.

“The more people who are vaccinated, the less likely they are to get the virus. If the virus cannot find the host, the person, the level of infection will automatically drop.”

CBC British Columbia will host the City Hall on March 10 to provide expert guests, including Dr. Bonnie Henry of the State Department of Health, with questions about the COVID-19 vaccine. You can find details at cbc.ca/ourshot.. Do you have questions about vaccines or deployment plans in BC? Send us an email: [email protected]