“It won’t be a zero to 100 type scenario where we had really great protection with [the] delta [variant] but now we’re going to go completely on the other side,” says Mansoor Amiji, university distinguished professor of pharmaceutical sciences and chemical engineering at Northeastern.
We still don’t have the data to show exactly how well a vaccinated immune system fares against omicron specifically, Amiji points out. But as long as it doesn’t evade those antibodies entirely, the existing vaccines — and booster shots — will still be key tools in fighting the pandemic, he said.
How can vaccines and boosters fight the new omicron variant?
There are two ways to strengthen your immunity: Make antibodies that are better at identifying and attacking the virus, or make antibodies in greater numbers.
When coronavirus enters through the nose or mouth, the virus works to bind to receptors on the surface of cells in the upper respiratory tract. The virus binds to those cells through what Amiji describes as a “lock and key mechanism.” Its outer spike protein is the key, and receptors on the cells are the locks.
The vaccines are designed to train the immune system to block that binding from happening. A vaccinated immune system creates antibodies that essentially form fake “locks” and bind to the spike protein on the viruses to prevent it from entering the cells.
The worry with the omicron variant is that the structure or shape of the spike protein is changing, Amiji said, but the vaccines have trained our immune system to identify the structure of the spike protein of the original strain of the virus.
But that doesn’t mean all will be lost.
While the antibodies may not be quite so adept at identifying and latching onto omicron, they likely still can much of the time.
A booster shot would also prompt the immune system to make more antibodies, he said. The idea would be that, even if those antibodies aren’t as good at targeting a specific variant, it would become a numbers game. The more antibodies in your body, the more chances they could counter all the viral particles and stop them from infecting your cells.
But there is also another line of defense our bodies can mount.
In addition to the antibody responses, Dr. Baozhong Wang, professor in the Institute for Biomedical Sciences at Georgia State University said the mRNA COVID-19 vaccines (Pfizer and Moderna) also induce robust T-cell responses that play an important role in immune protection. Those tiny white blood cells called T-cells help our immune system reject foreign substances in our body.
T-cells can continue fighting a virus after antibodies have waned. They are also less likely to be affected by viral mutations, such as those seen with the omicron variant, so they have a better chance at combating it and future variants.
What do we know about how well boosters work?
Moderna announced Monday that its booster shot, the equivalent of half of the dose of the first two, increased antibody levels against omicron by 37 times, based on preliminary data. Similarly, Pfizer said last month that its own booster shot improves protection against omicron “25-fold” compared to the first two doses.
Will we need an omicron-specific booster?
Maybe. The omicron variant appears to have significant mutations compared to previous versions of the virus, which may make it more likely to overcome immunity from vaccines or prior infections. But it will take weeks or longer for the data to come in on whether this is actually happening, and even more time to know what it would mean for people who are already vaccinated.
While it’s too early to know whether a variant-specific booster is needed, Pfizer, Moderna and Johnson & Johnson have said they are working on vaccines that specifically target omicron in case it’s needed. It would take about three months to develop a variant-specific shot.
Why get a booster now? Why not wait?
While there’s still a lot we don’t know, current vaccines could ultimately prove to be enough to protect against omicron, which is why the CDC is urging all adults to not wait.
But perhaps more urgently, getting boosted offers additional protection against the delta variant, still responsible for the vast majority of COVID-19 infections in Georgia and around the U.S.
Will people need to get a booster every year?
Maybe. Experts aren’t sure if the COVID-19 vaccine will be needed on a regular basis, like the flu shot.
Pharmaceutical companies are already preparing for annual boosters. Moderna is in the process of developing a single vaccine that covers COVID-19 and flu. Pfizer is in the process of developing a separate mRNA-based flu vaccine, which could be given at the same time as a COVID-19 vaccine.
But the necessity of an annual booster is still unknown. Experts say much will depend on the durability of the existing vaccines and boosters to protect people from severe illness, and how much the coronavirus changes over time.
So if you’ve already had a case of COVID-19 and are vaccinated, do you really need a booster?
Dr. Anthony Fauci recently said that a prior coronavirus infection acts as a primer and thereafter vaccination functions as a booster. Other experts say there is not enough data to know for sure, but early data suggests “hybrid immunity” conferred by a mix of an infection and a vaccine offers stronger protection than vaccination alone.
The immunological advantage from hybrid immunity, according to Wang, stems in part from what are called “memory B cells” or long-lived immune cells that are produced in response to an infection or vaccination.
Both vaccination and natural infection turn on memory B cells’ antibody-generating abilities. But research has found memory B cell levels can be higher in people who have been both naturally infected and vaccinated.
Vaccines and boosters in Georgia
The U.S. Department of Health and Human Services reported 152,787 booster doses administered in Georgia between Dec. 8 and Dec. 14, up 55% from the week before.
In Georgia, about 60% of the population has received just a single dose of vaccine, and 50.1% are considered fully vaccinated, or having received two shots of the Moderna and Pfizer shots, or one shot of the Johnson & Johnson vaccine.
Out of the Georgians considered fully vaccinated, about 1.2 million, or about 22.4%, have received a booster shot.