Escape artists: new Omicron subvariants dodge vaccines
COVID-19 Vaccines Omicron

Escape artists: new Omicron subvariants dodge vaccines

Santhni Subramaniam
Santhni Subramaniam

In 10 seconds? As the world is trying to shake off the Covid-19 pandemic, new Omicron subvariants are causing rising reinfection rates with the novel coronavirus sneaking through the protective walls of currently available vaccines and even reinfecting people within weeks.

What are these new subvariants? As we know, every time viruses make another copy of themselves, they undergo random errors in their genes causing mutations. The more a virus spreads through a community, the more chances they have to cause different mutations, eventually leading to a new strain, that is genetically different from its parent strain. Omicron variant (BA.1) was identified in the community in November 2021 and soon after, several sub-variants were found, namely BA.2, BA.3, BA.4, and BA.5, each more contagious and transmissible than the previous.

Okay so, is this really a threat? Omicron subvariants have many mutations on their notorious spike proteins that bind and let the virus enter our cells compared to the Alpha and Beta strains. Vaccines were initially produced based on the initial spike protein of Covid-19. Researchers have previously shown individuals vaccinated with either AstraZeneca, Pfizer, or Moderna vaccines to be less protected against Omicron. The latest study finds the new subvariant BA.4 and BA.5 (BA.4/5) to be 4.2-fold more resistant to antibodies present in fully vaccinated and boosted individuals than BA.2 subvariant. This is greater than the 1.8-fold resistance observed in BA.2.12.1 (a subvariant of BA.2). This suggests the new variants are getting better at evading the immune response from vaccinated individuals, leading to a rise in reinfection cases.

Do we see a rise in hospital cases too? A pre-print article (not peer-reviewed yet) reports the severity of Covid-19 in South Africa from BA.4/5 subvariants to be similar to the first Omicron variant, with better lower hospitalization rates observed for previously infected individuals who are triple vaccinated. A report from the UK shows hospitalization cases were on the rise (at the time of writing), albeit lower than the previous BA.1 and BA.2 waves.

Great, fewer people go to hospital… am I protected if I had an infection before and I’m vaccinated? Unfortunately, that is not the case. While some studies have shown a previous infection or vaccination to be protective, breakthrough infections are common. When looking at BA.4/5 activity against individuals who were vaccinated and had an infection with Omicron variant (BA.1), their antibodies were less effective at neutralizing the BA.4/5 strains. This shows evidence that the new strain can escape immune protection from previous infections or vaccination, hence causing many to experience another “breakthrough infection”.

How the spikes of the new subvariants look like? Source: B§ioengineer

Are we expecting restrictions in activities, i.e. social distancing or mask mandates? This is still a hot debate as infection cases and mutations are on the rise while in many countries social distancing restrictions have been lifted and overseas travel was allowed to return to normal. Nevertheless, precautions should be taken with reducing the chances of transmission by considering partial restrictions with social distancing.

If the old ones are weak… are there any new vaccines targeting Omicron? As the currently available vaccines were seen to be generally less effective against the Omicron variant, scientists are working hard for new approaches in the fight against Covid-19. An mRNA booster vaccine specifically targeting Omicron showed no improvement in protection in comparison to the Moderna mRNA vaccine. Pfizer has developed two new Omicron vaccines, with heightened immune responses compared to their earlier vaccine. According to a report on Pfizer’s webpage, a clinical trial conducted with over 1000 participants showed their new booster vaccines to offer up to a 19-fold increase in neutralizing geometric mean titers (GMT) (a measure of vaccine efficacy) against the BA.1 variant, but their effectiveness against BA.4/5 is yet to be studied.


A needleless vaccine

Trypanophobia, a fear of needles is one of the causes leading to vaccine hesitancy among individuals. A study reportedover 20% of individuals with blood-injection-injury fears (affecting 4% of the US population) were more likely to report Covid-19 vaccine hesitancy, compared to 11% of individuals who did not have the phobia.

As such, researchers have worked on needle-free alternatives to improve vaccine compliance among individuals. Jet injectors are currently being used to deliver new DNA-based Covid vaccines in Australia. The technology uses high-pressure to deliver vaccines across the skin barrier in a fraction of a second.

The hope is that the needleless technology will increase overall vaccine compliancy, improving population-wide protection against Covid-19.

Santhni has distilled 10 research papers saving you 35 hours of reading time.


The Science Integrity Check of this 3-min Science Digest was performed by Michael Eze.



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