I wrote today about infections after the 1st dose in Canada. There was plenty of info I didn't have room to include, so if you want to know more, come on a journey with me. Thread. https://www.theglobeandmail.com/canada/article-relatively-few-covid-19-cases-reported-after-receiving-first-vaccine/

First, a bit on the sausage-making. These data aren't public. They were the result of a request to PHAC made while @MariekeWalsh and I were working on this story. Most of the detail landed at 5 p.m. yesterday. https://www.theglobeandmail.com/politics/article-how-canada-can-prevent-a-fourth-covid-19-wave/

Here's what PHAC told us. As of April 26, they were aware of 2,274 infections reported two weeks or more after a 1st dose only. That works out to 1.3% of the 179,391 cases reported to PHAC since the rollout began. Of the 2,274, 203 people were hospitalized and 53 died.

Not in PHAC's reply was a stat I wish I had included but didn't, mostly because I was trying not to overwhelm readers with numbers. Mea culpa. The total # of people who had received one dose as of April 10 was 6,538,725, meaning 0.035% of partially vaccinated folks got COVID-19.

58% of the 203 hospitalizations were among cases aged 80 years and older, 22% among cases aged 70-79 years, 8% among cases aged 60-69 years, and the remaining 12% were aged 20-59 years. 91% of the 53 deaths were among cases aged 80+, while the rest were 50-79.

A note on the timing of these cases. Among the 53 deaths, date of death was available for 57%. Of these, date of death ranged from 22 to 62 days after receipt of first vaccine (median = 32 days).

Hospitalization date is not available for any of the 203 hospitalizations. The 203 hospitalizations ranged in case onset from 14 to 83 days after receipt of first vaccine (median = 24 days). 73% of hospitalizations became a case 14 to 30 days after receipt of first vaccine.

The timing of these cases is important. As several of the experts I spoke with mentioned, expecting robust protection right at two weeks after a first dose is a very high bar.

What these numbers don't capture, of course, is the people who were spared a serious case of COVID-19 because they received a first shot they would not have received had Canada doled out shots on time to fewer people.

FWIW, nobody on either side of the delayed dose debate thinks one shot is as good as two. Everyone wants to ensure people get both doses of a two-dose series. Get that second dose!

If you're a researcher or doctor who wants to know more, I'm happy to flip you PHAC's full answers. Shoot me an email. [email protected] (Crackpots need not apply.)