Well, it happened. Amid rising COVID-19 case numbers, your coworker or roommate or friend just tested positive. You're vaccinated, though, and you’re feeling fine. So, how scared should you be, exactly?
First, you can trust that you do have significant protection against the virus. (Yes, even against the highly contagious Delta variant.) In early tests, the Pfizer-BioNTech, Moderna, and Johnson & Johnson vaccines all proved to be highly effective at preventing symptomatic and asymptomatic disease, and even more effective at preventing death and hospitalization. This hasn't changed: Although some conservative pundits in the U.S. have argued otherwise, the Moderna and Pfizer vaccines are 95% protective against serious illness from the Delta variant, with two doses of AstraZeneca reported to be 67% effective against the Delta variant. According to a July epidemiology report from the Public Health Agency of Canada, 84.7% of Canadians hospitalized with COVID were unvaccinated. Per the same report, fully vaccinated people are 69% less likely to be hospitalized and 49% less likely to die from COVID than unvaccinated people.
That said, with new variants and increasing case numbers across the country, breakthrough cases (getting the virus after you are fully vaccinated) are expected to continue creeping up. As Dr. Zain Chagla, an infectious diseases specialist at McMaster University in Hamilton, ON told CBC of the Delta variant: "It's definitely going to be something we all encounter, at one point or another."
Which sounds scary, but doesn't necessarily have to be for those who are vaccinated. Data from Public Health Ontario showed that between December 14, 2020 and August 7 of this year, breakthrough cases accounted for less than 1% of COVID-19 infections in the province. While the Delta variant does add an additional layer of concern when it comes to the possibility of infection, in the past 30 days unvaccinated individuals were eight times more likely to contract COVID-19 than vaccinated people, according to Ontario public health. And recent cases in British Columbia showed a 10-times higher rate of infection among unvaccinated people and a 17-times higher hospitalization rate. And for those who are fully vaccinated and contract COVID, it's more likely than not that you'll have mild symptoms.
Still, newer data shows that you can pass the disease to others. "Infections happen in only a small proportion of people who are fully vaccinated, even with the Delta variant," the CDC in the U.S. reported in July. "However, preliminary evidence suggests that fully vaccinated people who do become infected with the Delta variant can spread the virus to others."
Just what to do if you're exposed to COVID-19 as a fully vaccinated person depends on which province you live in, as each has different guidelines. Fully vaccinated residents living in Ontario who are asymptomatic are advised to wear a mask and maintain physical distancing from others when outside their home, as well as monitor for any symptoms for 10 days following exposure. While public health advises they get tested ASAP via provincial clinics, these individuals aren't required to quarantine while awaiting test results. Those who are fully vaccinated but symptomatic after being exposed to COVID-19 should get tested ASAP and self-isolate until they receive their results. In provinces like B.C. and Saskatchewan, individuals who come into contact with a COVID-19 exposure don't have to get tested unless they develop symptoms, but the former requires residents to self-monitor for 14 days after exposure. It's important to check with your provincial health organization.
So, what now? Don't panic, mask up, and either get tested as soon as you can (within the three-to-five-day window, of course), or monitor for any symptoms. PCR tests are more accurate, but you can also start with a rapid antigen test: Just make sure to ask your provider about the specific test's accuracy rate, because they can vary. According to a Cochrane analysis of 64 medical studies, antigen tests can accurately identify 72% of symptomatic infections and 58% of asymptomatic infections, and also accurately rule out infection in 99.5% of people with symptoms and 99.5% of people without.
Breakthrough cases aren't common, but experts aren't surprised they're happening, either. It's important to remember that the COVID vaccines were never built to make anyone completely impenetrable in the face of the virus — they were meant to drastically reduce the chances of illness.
"The takeaway is that our individual risk is small, but our collective responsibility is great," MIT Medical Director Cecilia Stuopis wrote. "While we are well-protected by vaccination, to keep our community safe, we need to be willing to add additional layers of protection for now — masking indoors, distancing, and avoiding risky situations. The virus isn't going away, and we can't control how it will evolve, but we can control how we respond, and that can change the course of the pandemic."
COVID-19 has been declared a global pandemic. Go to the Public Health Agency of Canada website for the latest information on symptoms, prevention, and other resources.