STRAINED SITUATION

Health officials say evolution, carelessness are exacerbating COVID-19 mutations

When it comes to COVID-19, the combination of simple, Darwinian evolution and human carelessness can make an already bad situation worse.

The emergence of new, more infectious strains of the novel coronavirus doesn’t surprise two of Niagara’s top medical experts. They say rapidly expanding infection rates over the past few months, in Canada and around the world, have created the perfect platform for the virus to develop new adaptations that could make ending the pandemic more difficult.

“I don’t think it is a coincidence that we are seeing the emergence of these variants after we have seen so much spread of the virus,” said Dr. Mustafa Hirji, Niagara’s acting medical officer of health. “It gives the virus lots of opportunities to mutate.”

Public health measures meant to limit the spread of the virus — handwashing, physical distancing, wearing masks and staying at home — won’t just protect people but will prevent the novel coronavirus from being able to change and potentially become more dangerous, Hirji said.

Each time an organism reproduces — be it a mouse, or a bird or a bacteria — the offspring is slightly different than its antecedent. These genetic variants don’t often amount to much, said Dr. Karim Ali, Niagara Health’s top infectious disease specialist, and when these mutations do have an effect, they are often harmful to the organism. “But every once in a while, these mutations result in an adaptation that helps the virus survive,” Ali said.

If these novel adaptations are particularly successful at helping an organism survive, it will be passed on to its descendants and eventually outlast its less evolved kin. Pile up enough of these changes and over time an entirely new species will evolve.

For large, slowly reproducing mammals such as humans, this process takes thousands and thousands of years. But for microscopic creatures, like the novel coronavirus, with generations that live and die in an eye blink, the process can be much faster, Ali said.

He pointed to influenza as an example. The flu typically infects millions of people worldwide and, as a consquence, flu vaccines are frequently reformulated to keep up with the changing viruses.

The explosive growth of COVID-19 during the second wave of the pandemic provided ample opportunities for Darwin mechanisms to work, with each new generation of the novel coronavirus having the potential to craft useful adaptations — which is what happened in the U.K., Brazil and South Africa.

Ali said these variants all adapted in such a way to make it easier for the virus to use its spike proteins — the crown-like studs seen in images taken of the virus — to attack human cells.

Hirji said COVID-19 infections often depend on how much virus a person is exposed to. If the exposure is limited, a person’s immune system can fight the virus off quickly, leading to no or very mild symptoms. The adaptions of these virus variants allow it to get around that initial immune response more easily, he said.

Both the U.K. and Brazil variants have been detected in Ontario, although there are no confirmed cases of either linked to Niagara.

This process is why Ali said the “natural herd immunity” approach to fighting the virus adopted by a handful of countries, including Brazil, and advocated by some policymakers is both short-sighted and dangerous. The idea is that if the virus is allowed to spread virtually unchecked, eventually enough people will get sick, recover and develop natural immunity as a result.

But Ali said not only does this approach result in more serious illness, overwhelmed hospitals and preventable death, it creates the perfect laboratory for the virus to adapt new ways to attack humans.

It also means people who ignore or push back against public health measures and end up contracting COVID-19 are not only putting themselves and others at risk of infection, but are also offering their bodies up as a platform for viral adaptation.

Ali said there are a few silver linings to keep in mind when considering the novel coronavirus variants.

The adapted virus may be more contagious, but it does not appear to make COVID-19 more lethal.

Both companies have already begun work on a booster shot to their existing vaccines in response to the virus variants.