Health

Vaccines, Antibodies, & 2 Other Things To Know Right Now About COVID-19

A new set of coronavirus buzzwords to learn about.

An illustration of silhouettes in masks for a piece on new covid-19 buzzwords

(Photo: iStock)

In early 2020, when the COVID-19 pandemic swept through the world, there was a lot the world didn’t know about the disease. Now, for example, we know that social distancing, hand washing and wearing masks are effective public health measures against the novel coronavirus.

But as summer rolls into fall, there’s still a lot that’s hard to decipher. When will there be a COVID-19 vaccine? What exactly is a “reproduction number?” What is an antibody test? And what, if anything, do all of these things mean for Canadians?

Here is what Canadians need to know about COVID-19, half a year in.

What you need to know about the COVID-19 vaccine

Currently, there are more than 100 vaccine candidates that are in various stages of the research and trial process.

“Before December, we had no idea about this virus. So, to create a vaccine for it, we need to know exactly what the virus is,” says Dr. Alyson Kelvin, a researcher at the Canadian Centre for Vaccinology and Assistant Professor at Dalhousie University’s Faculty of Medicine. Once the Chinese government shared the virus’ genetic sequence on January 12, labs around the globe began designing vaccines.

There are several types of vaccines that are in development right now, each with different ways of teaching our immune systems how to fight COVID-19. Most of these vaccine candidates are in the pre-clinical evaluation stage, meaning that they have not yet been tested on humans. A handful of these vaccine candidates are in the clinical trial stage, which means they’re being tested on a very small sample size of human volunteers. Six vaccine candidates are the furthest along in their development and are currently in the third and final phase of the clinical trial stage, where the vaccine is given to a larger sample size of volunteers of all ages. Some of the vaccine candidates in phase three include the U.S.-based Moderna vaccine and the Oxford-based AZD1222, both of which have been making headlines recently. The trial process has been fast-tracked for COVID-19, with some phases happening simultaneously. Typically, it takes over 10 years for a vaccine candidate to go through pre-clinical development and the three phases of clinical trials. One country, Russia, has already approved a coronavirus vaccine: On August 11, Vladimir Putin announced that the country had approved a vaccine, but without any evidence of having conducted large-scale clinical trials, which—understandably—has experts worried.

There isn’t a timeline yet for when a vaccine will be ready and administered to the general population, and there is no indication yet from public health officials about how the vaccine will be rolled out. “There’s been lots of talk about whether high priority groups should get this first, which I’m in agreement with. All older individuals or immunosuppressed or healthcare workers or anybody on the front lines, you should get the vaccine first,” says Kelvin. “And then people who are less vulnerable would get [it] after.” This will also depend on which vaccine(s) are successful and produced, how many doses are produced, where the vaccine is from and what the deals are made for distribution in Canada (the federal government recently signed a deal with American pharmaceutical firms Pfizer and Moderna to secure millions of doses of their vaccine candidates if they prove successful).

There is also the possibility that there will be multiple vaccines available for Canadians—which is a good thing! It’s possible that the first vaccine that’s made and distributed won’t be the best possible vaccine for everyone for a number of reasons. Multiple vaccines on the horizon means that there’s potential for each person to find the best possible vaccine for themselves.

What you need to know about COVID-19 antibodies

“Antibodies are proteins produced by immune cells,” says Kelvin. “Once your body has come into contact with a pathogen such as a virus or a piece of a virus that might be included in a vaccine, your adaptive immune system […] can be ‘molded’ to specifically target the virus or virus piece it contacted.” Take the measles, mumps and rubella (MMR) vaccine for example. That vaccine uses a weakened form of the virus in order to teach your immune system to recognize and fight off the full virus, should it encounter it. Once your body has been “taught” how to fight off the infection, your body has gained the antibodies needed to fight measles, mumps and rubella and you have immunity.

Serological testing, or testing for antibodies, is not widely available for individuals in Canada, though at least one Toronto clinic will be offering the test—but you’d have to pay out-of-pocket for it. Public health authorities in Canada have been testing blood donor samples for antibodies to try to get a fuller picture of COVID-19’s spread. In July, the Canadian Blood Services and Canada’s COVID-19 Immunity Task Force found that less than 1 percent of the 10,000 samples collected so far came up positive for antibodies.

Though this number is small, it does show that there was undetected spread of COVID-19 in Canada—at the time that the antibody study came out, 0.3 percent of the Canadian population had tested positive for COVID. This low number also shows that the vast majority of Canadians—99 percent, according to this study—are still vulnerable to infection. According to Kelvin, antibody testing is also important in determining if a vaccine worked at stimulating an immune response. “The major goal of a vaccine is to induce virus-neutralizing antibodies in a person after vaccination. That way they will have antibodies that are able to specifically attach to a virus and block it from infecting our cells.”

The New York Times recently reported that “Scientists who have been monitoring immune responses to the virus are now starting to see encouraging signs of strong, lasting immunity, even in people who developed only mild symptoms of Covid-19, a flurry of new studies suggests. Disease-fighting antibodies, as well as immune cells called B cells and T cells that are capable of recognizing the virus, appear to persist months after infections have resolved — an encouraging echo of the body’s enduring response to other viruses.”

What you need to know about R0

R0, pronounced R-naught, represents the basic reproduction number of a virus. Simply put, R0 represents the number of other people that a single infected person infects. Epidemiologists use R0 to measure the infectiousness of a new disease, where no one in the population is immune and there are no interventions in curbing the spread of the disease. If the R0 is more than 1, that means the number of people infected is growing.

Without any public health measures in place, R0 is currently estimated to be between 2 and 3—meaning that for every single person infected, they infect 2 to 3 others. This number varies depending on your location so it’s really just an overall estimate. “[R0] is affected by environmental conditions and the behaviour of affected populations,” explains Dr. Selena Sagan, the director of the Canadian Society for Virology and Associate Professor of Microbiology, Immunology, and Biochemistry at McGill University. “So, for example, R0 might be slightly higher in dense populations than in spread-out areas.”

As Canada reopens and physical distancing measures are loosened, it’s possible that the R0 may increase—meaning that COVID-19’s rate of infection may go up as we ease the countermeasures that have kept the virus in check so far. “We should be doing our part to keep R0 as low as possible by social distancing, taking seriously the public health guidelines and really not getting into COVID complacency,” says Sagan.

What Canadians need to know about flu season and the flu shot

As the weather gets colder, the flu season arrives. This year will be no different. Every year in Canada, there are approximately 12,200 flu-related hospitalizations and 3,500 deaths.

Though physical distancing and other COVID-related public health measures may curb this year’s flu season, getting a flu shot should still be a priority for everyone. “When you get the flu, your immune system is lowered and that might make you more susceptible to COVID-19,” Kelvin explains. Getting your flu shot will also help to decrease the burden on our hospitals and healthcare system. By minimizing your chance of getting the flu and giving it to others, you’re also minimizing any possible overflowing of the healthcare system.