The latest:
Ontario public health units will be able to access rapid antigen test kits from the province to help prevent outbreaks at schools or child-care centres, the province’s chief medical officer of health said Tuesday.
The province foresees rapid antigen screening being used only for unvaccinated asymptomatic students and children who are not high-risk contacts. Symptomatic or high-risk contacts should continue to access lab-based PCR testing at assessment centres, said Dr. Kieran Moore.
“This is an extra tool in our tool chest to keep schools open,” said Moore, who added that public health units will have to assess their local case ratios to determine whether the tests should be utilized.
Public health experts say rapid tests can help break potential chains of transmission as they fare well at detecting persons with high viral loads, while reducing the strain on labs that perform PCR tests. Parents say the tests can help prevent their own work disruptions, as they are not pulling out their asymptomatic and COVID-negative children out of class for several days of remote learning in the face of one or two positive cases at their schools.
The announcement comes after groups of parents had organized surveillance testing for their schools using the rapid test kits, but the government told agencies to stop distributing them to anyone but businesses.
Moore, who in recent weeks has focused on the false positives that some brands of antigen tests produce, said the highly transmissible delta variant led to an evolution in approach. He also described it as unfortunate when children have to quarantine for up to two weeks at a time, as occurred in the last school year.
But, he said, widespread regular testing was not practical given that there are about two million students in Ontario elementary and secondary schools.
Ontario on Tuesday reported three additional deaths from COVID-19 and 429 new cases, with the seven-day average of new daily cases falling to 576.
![](https://thumbnails.cbc.ca/maven_legacy/thumbnails/495/663/mpx-CLIP-PRETAPE-DOC-TALK-KIDS.jpg?crop=1.777xh:h;*,*&downsize=510px:* 510w")
Ian Hanomansing speaks with pediatric infectious disease specialist Dr. Fatima Kakkar about the rise in COVID-19 transmission among kids, and when children aged five to 11 can expect to get vaccinated. 1:19
What’s happening with vaccines
Johnson & Johnson says it has submitted data to the FDA for emergency use authorization of a booster shot of its single-dose COVID-19 vaccine in people aged 18 years and older.
J&J on Tuesday said its submission includes data from a late-stage study that found a booster of its vaccine given 56 days after the primary dose provided 94 per cent protection against symptomatic COVID-19 in the United States and 100 per cent protection against severe disease, at least 14 days after the booster shot.
The FDA has already authorized a booster dose of the vaccine developed by Pfizer Inc. and partner BioNTech for 65-year olds and older, people at high risk of severe disease and others who are regularly exposed to the virus. Moderna submitted its application seeking authorization for a booster shot of its two-dose vaccine last month.
J&J said it plans to submit the data to other regulators, the World Health Organization and National Immunization Technical Advisory Groups to inform decision-making on local vaccine administration strategies, as needed.
Meanwhile, AstraZeneca has requested emergency use authorization from U.S. regulators for its new treatment to prevent COVID-19 for people who respond poorly to vaccines because of a weakened immune system.
In a statement on Tuesday, the Anglo-Swedish drugmaker said it included data in its filing with the Food and Drug Administration from a late-stage trial that showed its antibody therapy called AZD7442 reduced the risk of people developing any COVID-19 symptoms by 77 per cent.
While vaccines rely on an intact immune system to develop targeted antibodies and infection-fighting cells, AZD7442 contains lab-made antibodies designed to linger in the body for months to contain the virus in case of an infection.
A U.S. authorization for AZD7442 — based on two antibodies discovered by Vanderbilt University Medical Center in the United States — could be a major win for AstraZeneca, whose widely used COVID-19 vaccine has yet to be approved by U.S. authorities. Trial results on the AZD7442 therapy, first published in August, were taken three months after injection, but the company hopes it can tout the shot as a year-long shield as trial investigators will follow up with participants as far out as 15 months.
What’s happening across Canada
![](https://thumbnails.cbc.ca/maven_legacy/thumbnails/906/299/COVID-ICU-ALBERTA-REPORTERLESS-041021.jpg?crop=1.777xh:h;*,*&downsize=510px:* 510w")
Alberta’s ICUs have 257 COVID-19 patients. That’s more than any other province. But the number alone doesn’t explain the impact. In a place where small details and moments matter, struggling ICUs mean struggling patients. This is the situation they see. 11:32
What’s happening around the world
As of early Tuesday, more than 235.4 million cases of COVID-19 had been reported worldwide, according to Johns Hopkins University’s coronavirus-tracking tool. The reported global death toll stood at more than 4.8 million.
In Asia, China reported no new local COVID-19 cases for the first time in more than three weeks.
In Europe, the Kremlin has implored people to get vaccinated, as Russian authorities mulled reintroducing health restrictions to cope with daily cases rising to their highest levels since January.
In the Americas, New York State’s largest health-care provider has fired 1,400 employees who refused to get vaccinations.
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