- The combination of vaccination and immunity from natural infection produces strong protection, data suggest.
- Most data we have is from the time when Delta was dominant, but emerging evidence suggests the same could be true for Omicron.
- Exposure to Omicron and other variants may diversify the immune response to any strain of the virus.
As people rack up boosters and breakthroughs, immunity has become a complicated buzzword in our coronavirus vocabulary.
"Breakthrough" infections surprised a small portion of the vaccinated population and showed us all that our protection is not necessarily variant-proof, although vaccines still work well for preventing severe outcomes.
However, emerging evidence suggests there may be a silver lining for people who got COVID after vaccination: People who are fully vaccinated and have immunity from a prior COVID-19 infection seem to be very well protected against future infection.
The researchers behind one recent study at Oregon Health and Science University, conducted during the Delta wave, described this double-duty protection "superimmunity" — a finding reinforced by recent CDC data suggesting people with both a vaccine and a prior infection were the least likely to contract COVID-19 with Delta.
While data on Omicron is still trickling in, early research out of Austria (not yet peer-reviewed) suggests the same may be true for vaccinated people who got COVID in recent weeks.
But a new type of immunity does not mean the end of COVID-19. It represents yet another fracture in this patchwork pandemic, with some people more protected than others. Another variant could emerge at any point. For public health experts, the worry remains that a COVID-19 infection is unpredictable.
"You'd be crazy to try to get infected with this," Dr. Robert Murphy, of Northwestern University Feinberg School of Medicine, told CNN. "It's like playing with dynamite."
Vaccination provides a foundation for 'superimmunity' if you're infected later on
Superimmunity doesn't work without the foundation of vaccination in place — a natural infection alone isn't going to deliver anything beyond normal immunity, potentially high medical bills, and the risks of severe sickness and long COVID.
Vaccinated people who experienced breakthrough infections during the Delta wave produced antibodies at levels up to 1,000% more effective than those generated after a second Pfizer shot.
"Not only is the level of the antibodies high, but the ability to cross-neutralize different variants is remarkably high," Fikadu Tafesse, a co-author of the Oregon study, told Insider.
By exposing your immune system to multiple variants of the same virus, you're essentially showing your body the many forms the coronavirus can take on.
"The vaccines were designed with the original strain, but when you get the breakthroughs, it could be Delta or now Omicron," Tafesse, an assistant professor of microbiology and immunology, added. "It gives you an additional level of complexity in terms of your antibody diversity."
What a natural infections does to the immune system
While you were bedridden with fatigue and body aches, your T cells and B cells were hard at work. These immune warriors are responsible for attacking infected cells and making more antibodies, respectively. The overall result is a better-trained defense plan for the next time your body encounters the virus.
"The whole virus infection trains your immunity in a more complete way than the immunity we get from the vaccine, which is mostly spike protein," Tafesse told Insider.
The vaccines use the spike protein — the virus' weapon for infiltrating our cells — as a shortcut to immunity. But with Omicron, we've learned that an immune response specific to a single protein won't always keep people from getting COVID-19.
It'll take time to track Omicron-induced immunity
The researchers haven't yet gathered the data to understand how superimmunity holds up against Omicron, but Tafesse was optimistic.
"We think that individuals with breakthroughs will have high levels of protection, even from Omicron," he said, but he laughed at the prospect of trying to predict what comes next. "I mean, we say that now it's superimmunity, so what is the next one — super-duper immunity?"
In a recent panel put on by the World Economic Forum, Dr. Anthony Fauci said the questions of whether Omicron would bring the pandemic to an end — or perhaps a slow fizzling out — are tough to answer given the virus' potential to mutate.
"I would hope that that's the case," Tafesse said when asked if COVID-19 would become endemic after Omicron. "But that would only be the case if we don't get another variant that eludes the immune response of the prior variant."