Fighting Omicron requires boosters: USask health and epidemiology expert

Community health and epidemiology researcher Dr. Nazeem Muhajarine (PhD) of the College of Medicine is one of several University of Saskatchewan (USask) experts who is tackling health issues raised by COVID-19. 

Dr. Muhajarine helps to give us a sense of the Omicron variant, and the importance of boosters and how they work to fight off COVID-19.

Omicron seems to be breaking through our immunity with a high infection rate. What makes Omicron different?

The Omicron variant of concern appears to be much more contagious than the Delta variant, in the order of three to five times more. The virus has a genome profile that is quite different from Delta and other previous variants of concern, with its 50-plus mutations. Many of these mutations were seen in the other variants, but this has encompassed them all in one variant. That’s a very important difference. 

All of these mutations makes it much more effective and efficient in getting inside human cells. Omicron attaches to and gets into the cells better; it can multiply and replicate at a greater rate in comparison to Delta. More than other variants of concern it can evade antibody detection. Omicron has a shorter incubation time and a shorter cycle in human cells. So from beginning to an exposure to resolution, Omicron can go through many cycles quickly, which aids in the spread. On the plus side, if there is a plus side, we are seeing that Omicron causes less severe symptoms in individuals than Delta. However, again, given its exponential growth, society-wide it is creating more disruptions.

There still seems to be some hesitancy to get boosted. Why are booster shots important for the community?

Since the early days of the vaccine rollout, we always knew we would probably need a booster, but COVID variants like Omicron and Delta have really hastened the need to get a booster dose after the two primary doses of vaccination.  

Simply put, booster doses, even against Omicron and Delta, protect you from severe COVID and death. The data is clear that those who have booster doses, compared to those with only two doses or no vaccines, are 15-20 times lower hospitalization rates or death. It is actually quite remarkable, even with Omicron, the protection against severe COVID and death that booster doses give. This is particularly true for older people, those who are immunocompromised or are otherwise vulnerable. Studies also show that some of the most powerful protection is generated when people who have had COVID are also vaccinated, including a booster. So we know that getting a booster dose is really important to helping to end COVID. We want people to get the booster doses because people with three doses are protected that much more, and it is a necessary thing for us to do to protect each other. 

What is meant by natural immunity vs. vaccinated immunity? And what is meant by waning immunity? 

The immunity acquired by catching COVID-19, that is what is referenced as having a natural immunity, as opposed to immunity acquired through vaccines. The fading of the immune response, especially antibodies, which is our first-line of defence, over time, is a natural occurrence. We expect it to happen, and it is nothing to worry about. At a deeper level, the cells carry the memory of this pathogen, and if they detect it again, they will quickly be able to mount a defence. This is why even if Omicron is able to break through the antibody defences in some cases, the cell-mediated immunity can protect us from severe consequences. Back to the booster doses again, this is an additional dose given after the protection provided by the original shot(s) has begun to decrease over time. It helps you to maintain your level of immunity for longer.

Will Omicron hasten the move to COVID endemicity? And what can we do to keep the community safe?

Increasingly it is looking like it would. The best data that is comparable to us come not from South Africa, but from the U.K., and now even from our own Canadian provinces where Omicron hit first, and hard, Quebec and Ontario. In these provinces, we are seeing the Omicron wave reverse course and fall as fast as it skyrocketed in December. It is too early to say how long the Omicron wave will last in all the provinces and territories in Canada, but the early data on the downslope of the wave is showing that it had taken six to seven weeks to crest rather than much longer, for example, eight to 10 weeks it had taken with the previous waves. This means that by the second week in February we could expect to see Saskatchewan’s Omicron wave on a steep descent as well.

In the meantime, we need to further increase our booster shot uptake in 18 and older, and vaccine uptake in our kids. This will blunt the sting of the Omicron case rate but, more importantly, it will protect those with vaccines from getting severe COVID and death. 

We also need to continue to protect our health-care workers (because without them being healthy the whole health-care system is compromised), immunocompromised people and those who live in congregated care settings, because they are especially vulnerable to severe COVID outcomes, and the kids. We need to watch out for long COVID. On a bit of positive note, we now know a lot about COVID, and with the vaccines we have, we feel this wave we are currently experiencing might be the last wave of any significance to contend with.