Thread by @sailorrooscout

A study of 1M+ people in Canada found two doses of any of the three COVID-19 vaccines (Moderna, Pfizer, AstraZeneca) led to strong protection from infection, hospitalization, AND death -even against Delta- REGARDLESS of the vaccination combination and showed NO signs of waning.🧵

Data from researchers at the British Columbia Centre for Disease Control (BCCDC) and the Quebec National Institute of Public Health (INSPQ) showed two doses of mRNA and/or AstraZeneca’s vaccine gave excellent protection against hospitalization, with NO SIGN of decline

by 5-7 months post-vaccination. In addition, a 7-8-week interval between doses improved vaccine efficacy and may be optimal in most circumstances. Findings indicate prolonged two-dose protection and support the use of mixed schedules and longer intervals between doses.

Please KEEP IN MIND: these results are during the period when the Delta variant was not just circulating but PREDOMINATING that researchers saw such high protection nonetheless against both infection and hospitalization. 95% effective against hospitalization as a matter of fact,

and that is REGARDLESS of the approved vaccination combination. This means that for every 100 unvaccinated people severely ill in Canadian hospitals, 95 of them COULD HAVE been prevented by receiving two doses of either AstraZeneca’s, Pfizer’s, or Moderna’s vaccine, OR some

combination of the three. Researchers found protection was even stronger when the interval between the first and the second doses was more than six weeks apart. In fact, the research showed that protection against COVID-19 infection from two doses of Pfizer’s vaccine ROSE when

the first and second doses were spread out- from 82% three or four weeks, to 93% after four months. Note- this is JUST against infection. If you received your doses with a three or four week interval, please don’t fret. The protection IS still high (see graphics below).

For those who received AstraZeneca’s vaccine as their first dose, their protection against any infection was lower than for mRNA vaccine recipients, BUT they had comparable protection against hospitalization- that IS the MAIN goal. For those who received a first dose of

AstraZeneca and a second dose of an mRNA vaccine, their protection was AS GOOD as those who had received TWO mRNA vaccines. In other words, the mix-and-match schedules are protecting extremely well. Countries who don’t recognize mixing vaccines as “fully vaccinated” may want to

reconsider that decision regarding international travel policies based on this data. In addition, this VE analysis showed that this strong protection of more than 80-90% across the board has been maintained for AT LEAST (NOT ONLY!) 5-7 months after the second dose and has shown

NO signs of waning. The first groups to get vaccinated in British Columbia were healthcare workers and older adults. These individuals were most at risk of acquiring and spreading COVID-19 or becoming severely ill. In further VE analyses, findings show that strong protection is

also maintained in health care workers and older adults living in the community. In both provinces, two doses of homologous or heterologous SARS-CoV-2 vaccines were associated with ~95% reduction in the risk of hospitalization. VE EXCEEDED 90% against SARS-CoV-2 infection when at

least one dose was an mRNA vaccine, but was lower at ~70% when both doses were AstraZeneca. Estimates were similar by age group (INCLUDING adults 70-years-old) and for Delta-variant outcomes. VE was significantly HIGHER against both infection and hospitalization with longer

7-8-week vs. manufacturer-specified 3-4-week interval between doses. Two-dose mRNA VE was maintained against hospitalization for the 5-7-month monitoring period and while showing some decline against infection, remained 80%! You can find this study here: medrxiv.org/content/10.110…