Covid-19 vaccines still effective against Omicron, experts assure

Current data shows Covid-19 vaccines administered in South Africa are holding up well against the new Omicron variant. 

As of Friday, 43% of adults had received at least one dose of the Pfizer vaccine, or the single-dose Johnson & Johnson (J&J), Department of Health Minister Dr Joe Phaahla said during the weekly Covid-19 briefing. 

Phaahla confirmed that rapid antigen tests and polymerase chain reaction (PCR) test were also detecting the variant. Current treatment methods, such as steroids, oxygen, antivirals and anticoagulants are also still relevant. 

The news of vaccines doing well in protecting people comes at a time where the Omicron variant’s child-infection rates have dropped from 21% to 8%. 

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Phaahla said more adults were now becoming infected, with the most hospital admissions being 30-to-39 year olds. 

Proof of vaccine efficacy

Professor Alex Sigal from the Africa Health Research Institute, who along with Sandile Cele were the the first in the world to grow the Covid-19 virus in a test tube,have been hard at work doing laboratory neutralisation experiments using the Pfizer two-dose vaccine.

Sigal said the variant used the same receptors as the ancestral Covid-19 virus, which means this variant has not changed how the virus behaves. 

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Vaccines neutralise illicit antibodies to help the body fight a virus.

Sigal and his team found with current vaccines, there was a decrease in illicit antibodies shutting down Omicron, compared to other variants. 

However, he emphasised that this did not decrease to non-effective levels. 

In other words, current vaccines are not as effective against Omicron as they are with other variants, but they do still provide significant protection.

“How well the vaccine works for preventing infection depends on how much antibodies you have,” Sigal said.

Booster shots will help

Pfizer provides around 70% protection after two doses are received. 

The main reason there is a strong decrease in the vaccine’s ability to neutralise Omicron is because this is a different variant to the one the original vaccine was designed against. 

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Pfizer data indicates that booster shots provide very little decrease in neutralising Omicron, meaning it is able to fight the variant even better. 

Sigal and his team concluded that protection from infection would go down with the current variant, but this is not a reason to conclude that vaccines do not protect a vaccinated person from severe disease.

He said people also had T-cell immunity, which is less affected by virus mutations. 

At present, good protection comes from being previously infected with Covid-19 and being vaccinated. 

Sigal and his team urged those who had not yet been vaccinated to do so, as this was the best protection against severe illness.