Waiting for the public to develop “herd immunity” to COVID-19 is not a practical strategy to fight the pandemic, would put many lives at risk and possibly overload the health-care system, Alberta’s top doctor says.
Herd immunity, when a certain percentage of the public develops resistance to an illness, has been touted in some circles, including by a top adviser to U.S. President Donald Trump, as a possible solution to the pandemic.
For COVID-19, estimates of that percentage range from 50 to 70 per cent of the population, Dr. Deena Hinshaw, Alberta’s chief medical officer of health, said Monday at a news conference. Studies in Canada, she said, have estimated that only about one per cent or less of the population has been infected.
Hinshaw said she has heard suggestions that, because younger people are generally at low risk of severe outcomes, Alberta should protect older people but otherwise let the virus spread as quickly as possible to build up a collective immunity.
“The suggestion, however, does not take into account the drawbacks of this approach,” Hinshaw said.
“It is important to remember that COVID-19 is able to spread rapidly, and we are all interconnected. Adopting a herd immunity approach would have a serious and deadly impact on many people in the population.”
While it’s true that COVID-19 rarely kills young people, in Alberta the illness has been fatal for about 18 per cent of those over the age of 70, and for about 30 per cent of those over the age of 80 who are residents of long-term care centres, she said.
Even if perfect protections were in place for those who live in nursing homes and seniors centres, letting the virus spread freely through the rest of the population would put many lives at risk, Hinshaw said.
“The more community transmission that we see, the greater the risk of it spreading to older and at-risk Albertans. The lives of people with chronic conditions, and our elders, are very important. Adopting an approach focused on herd immunity would place many older Albertans, or those with underlying medical conditions, at risk, and lead to many more deaths across our province.”
Hinshaw said the public should remember that while death is the worst outcome, it is not the only severe outcome. Over the past seven months, one in 67 people aged 20 and 39 who have been diagnosed with COVID-19 have needed hospital care. That rises to one in 18 people for those aged 40 to 69, and one in four for those aged 70 and over.
“If we let the virus spread freely, our health system could be overloaded in caring for COVID patients, which would challenge our ability to provide all the other health services that we need.
“Babies are still being born, car crashes are still occurring and our health system still must support Albertans in countless other ways. We have seen this overload happen in other countries. We do not want it to happen here.”
Long-lasting immunity uncertain
It’s also important to remember that physicians and experts don’t yet know if being infected with the coronavirus leads to long-lasting immunity. That could mean that the extra costs of widespread transmission, including many more deaths and risks to so many people’s health, could be for nothing, she said.
“We would put our elders and those with chronic conditions at risk, increase the burden on our acute-care system, and still may not get the collective protection that this approach was designed to achieve,” Hinshaw said.
“Given that, what is our best path forward? First, we must rely on science. A great deal of research around the world is underway to find effective treatments and a safe and effective vaccine for COVID-19.
“Second, as we wait for treatments and vaccines to be discovered, we need to find a balance between preventing the harms of COVID-19 and preventing the harms that strict restrictions can have on the rest of our health. This balance is delicate and dynamic.”
Collectively following public health guidelines about mask wearing and distancing are still the keys to protecting the population, Hinshaw said, both from the virus and from a return to the stricter rules people lived under a few months ago.