A new study involving tens of thousands of participants in Qatar found that a single dose of the Pfizer-Bionek corona virus vaccine in Ontario is now only 30 percent effective in preventing infection, and only 55 percent effective in preventing hospitalization or death.
Following the effects of nearly 40,000 people tested for COVID-19 in Qatar, The study was published in the New England Journal of Medicine on Wednesday Pfizer jabin was only 29.5 percent effective in preventing a shot infection, asymptomatic or otherwise.
One shot of Pfizer was found to be 54.5 percent effective in preventing “severe, critical or dangerous” consequences due to infection of the B.1.1.7 variant.
Public Health Ontario In recent weeks, it appears that more than 90 percent of positive samples on screens have the characteristics of the B.1.1.7 variant first discovered in the UK last year.
In those receiving both doses, the effectiveness of the vaccine against B.1.1.7 with or without symptoms was 87 percent, which increased to 90 percent 14 days after the second dose.
It was 100 percent effective against severe symptoms or death.
“In Qatar, as of March 31, 6689 people had received a single dose of the vaccine and 1,166 had received two doses of advanced infections,” the authors wrote. “Seven deaths from Covit-19 have been reported among vaccinated individuals: five after the first dose and two after the second dose.”
The Qatari study detected poor performance and used a large sample size Than many The National Advisory Council on Disease Control (NACI) is used to justify its original recommendation to go into space within 16 weeks of studies and databases.
Other studies, cited by NACI, have found that a single dose of a corona virus vaccine is 65 to 80 percent effective in preventing serious side effects.
NACI cited the British example, but the levels there were mostly only 12 weeks apart. The WHO itself has recommended a maximum of six weeks interval, but only in complex situations.
Ontario officials have suggested that the gap between the first and second levels could be narrowed soon if the increase in supply continues, but no concrete policy changes have been made.
Pfizer Corporate Affairs Director Christina Antonio CB24 said their position was to provide vaccine doses at 21-day intervals for maximum effectiveness.
“We have no Pfizer-led data on the single-dose approach. Our current research specified two levels at intervals of 21 days. Our position has not changed.
Although three other vaccines are approved for use in Canada, Pfizer-Bioentech is the most widely used vaccine in Ontario.
Using data from the first 3.5 million volumes managed in Ontario between December 2020 and April 2021, epidemiologist Dr. Jane Chokla said the current gap-narrowing strategy was very effective.
From Canada’s immunization campaign began in mid – December 2020 to late April 2021, nearly 6,800 people have been infected with COVID – 19 after receiving one vaccine.
“Of these, 4,515 cases were reported within 14 days of the first vaccination, and 2,274 cases were reported in at least 14 days,” a Health Canada spokesman told CB24 last week.
Qatar’s experience shows similarities with Ontario, even though the province is Qatar dwarfed in terms of population.
Varieties B.1.1.7 and B.1.351 in Qatar dominated in mid-March over the previous “wild” type known as COVID.
With regard to the B.1.351 variant first detected in South Africa, this study also yielded poor results from a single dose.
The study found that a single dose of the Pfizer-Bioentech vaccine was only 17 percent effective in preventing infection by P.1351.
It was found to be zero percent effective in preventing hospitalization or death due to P.1.351.
The P.1351 variant is only occasionally detected in Ontario, with only 246 examples detected in the past month.