COVID-19 vaccine one important line of defense for students, but not the only one, says virologist

Vaccination is an essential defence against COVID-19, particularly for kids as they head back to school this week, but it shouldn't be the only precaution taken, according to a University of Saskatchewan virologist.

Everyone should take several basic safety measures to slow the spread of the Omicron variant, said Angela Rasmussen, an expert in emerging global viruses at the U of S Vaccine and Infectious Disease Organization (VIDO). 

People should limit indoor contacts, use high-quality masks and pick up a box of free rapid tests to deal with the latest wave of the pandemic, she said.

Rasmussen spoke to Saskatoon Morning host Leisha Grebinski.

This interview has been edited and condensed.

CBC: We're facing a fifth wave here driven by the Omicron variant. Why is a booster shot so important? 

Rasmussen: The booster shot, it turns out, is really important in terms of reducing your risk of contracting Omicron and also making sure that your protection against severe disease remains high. Some studies have shown that two doses of the vaccine provide pretty good protection against severe illness.

It's good news in the sense that there is still protection against severe disease, but they found that with a booster shot, it also improved protection against getting infected in the first place, taking it back up to about 70 per cent. And it really did boost the protection against severe disease back up into that 90 per cent range. Getting a booster shot will also improve the protection you have that will help keep you out of the hospital if you do happen to have a breakthrough case. 

CBC: There are some skeptics who are asking: 'If the vaccine is not 100 per cent effective against the virus, why get it?' 

Rasmussen: Well, as I mentioned, a vaccine will keep you out of the hospital. Ideally, we don't want to get infected at all, but there are lots and lots of vaccines that don't provide 100 per cent protection against infection. The inactivated polio vaccine is a great example of that. The purpose of vaccines really is to prevent people from getting sick, to prevent disease. It's not necessarily to prevent infection.

Now it's very nice, of course, when a vaccine does provide what we call sterilizing protection, meaning that it prevents you from getting infected. But the real key here is if you do get infected, that vaccine will allow your body to fight off the virus very quickly, and that will keep you from getting very, very sick. So in that sense, the vaccines are still doing what they're supposed to be doing. And. as I mentioned before, a booster shot will increase your protection against getting infected in the first place as well. 

CBC: Now let's talk about the naming of a booster shot a third dose. What's the difference between calling it a dose and and a booster? How common are three dose vaccines?

Rasmussen: Well, the three dose vaccines are extremely common, and I think this is also something that a lot of people have had questions about. People want to know, are we going to have to be getting boosters every six months, every three months for the rest of our lives? And the answer to that is probably not. There are a number of vaccines that we get throughout our lives and especially in childhood that are three-dose or sometimes four-dose vaccines — the HPV vaccine, the Hepatitis B vaccine, the inactivated polio vaccine, the MMR vaccine. I could go on and on and on.

It's very, very common for vaccines to basically require three or four doses. And the reason for that is vaccines are essentially like a class for your immune system. They're training your immune system to recognize a specific virus or pathogen. In this case, if you send your immune system to multiple classes, then it's going to be better equipped to recognize that virus once it encounters it in the real world. And that appears to be the situation with our COVID vaccines now.