COVID: Omicron BA.2 infection after vaccine can protect from BA.4/BA.5 - study

People who took the Pfizer/BioNTech vaccine against COVID-19 and suffered from a breakthrough infection of Omicron BA.2 may have strong antibodies against the highly contagious coronavirus subvariants of Omicron BA.2.12.1 and BA.4/BA.5, according to a new study.

The findings of this study, published Tuesday in the peer-reviewed academic journal Science Immunology and led by BioNTech researcher Alexander Muik, sheds light on the development of immunizing antibodies against the highly contagious COVID-19 Omicron subvariants, which in turn can help with the development of a new vaccine specifically targeting Omicron BA.4/BA.5.

Background: Coronavirus Omicron variant: The most contagious spreader of COVID-19

The Omicron variant is the most contagious form of the novel coronavirus SARS-CoV-2, which causes COVID-19. It has infected millions of people across the world and has helped keep the pandemic alive after over two years.

There are different forms of the Omicron variant, specifically in its subvariants. The ones that derive from Omicron BA.2, such as BA.4/BA.5 and BA.2.12.1, are among the most dominant strains causing COVID-19 in the world.

All of this is despite the widespread distribution of COVID-19 vaccines, with chief among them being the mRNA vaccine designated BNT162b2, created by Pfizer and BioNTech. This was among the first to really see use during the pandemic and it has been widely successful around the world.

Still, the vaccine isn't perfect at stopping the spread of COVID-19, though it does drastically lower the risk of contracting a serious case. In other words, vaccinating against COVID-19 can keep you safe from getting seriously sick.

What are breakthrough infections?

A breakthrough infection refers to when someone is infected with a disease despite being vaccinated against it. 

This is not something unique to COVID-19, though the pandemic did help raise awareness of it, and can be caused by a number of factors. 

However, they aren't always a bad thing.

Being infected with a disease is a way to create antibodies, and while it is generally effective at doing so, it isn't necessarily more effective than a vaccine, and certainly is not safer. 

But breakthrough infections, which happen despite the presence of antibodies, are no exception to this and also create antibodies themselves.

What this means is that according to many studies and observations, breakthrough COVID-19 cases are not only not as serious, but they can also create a "super immunity" of sorts.

However, viruses sometimes have ways around this through mutations and evolutions. This can mean that what helped keep the virus out at one point might not work the same a second time.

Indeed, this is part of the reason why there is such a large effort to find a vaccine specifically for the dominant subvariants of Omicron.

But that is where this study comes in.

Neutralizing antibodies for COVID-19 Omicron subvariants

The original Omicron variant was known as Omicron BA.1. This form of the coronavirus was very good at infecting people due to an alteration in its spike protein. However, a new subvariant, Omicron BA.2, soon displaced it as the most dominant strain in the world.

But this in turn saw BA.2 be replaced by its own descendants, BA.2.12.1, BA.4 and BA.5, which currently dominate the world.

Because of how different they are, protections against BA.1 do not necessarily work as well on the descendants of BA.2. 

This raised the question behind the study: Can BA.2 breakthrough infections help create more neutralizing antibodies against BA.4 and BA.5?

To figure this out, the researchers studied samples from a few different demographics, specifically those who were triple vaccinated against COVID-19 and had suffered a breakthrough infection from Omicron BA.1, those who suffered from a breakthrough infection of Omicron BA.2 and those who didn't at all. 

The findings indicate that the hypothesis the researchers held was correct. A breakthrough infection of Omicron BA.2 was far more effective - at least twice as effective - at producing neutralizing antibodies for BA.4 and BA.5. 

The conclusion: A COVID-19 vaccine adapted to the Omicron BA.2 subvariant or its descendants may be more effective at providing protection against future variants of concern and the existing predominant coronavirus sub-lineages.