Are COVID-19 Vaccine Boosters Effective Against Omicron Variant?

Published December 1st, 2021 - 09:16 GMT
covid-19 vaccine second jab or booster in last 6 months are protected against Omicron
The Pfizer Covid-19 vaccine is administered at a pop-up clinic offering vaccines and booster shots in Rosemead, California on November 29, 2021.(Photo by Frederic J. BROWN / AFP)
Israeli health chiefs announce first signs vaccines are effective against Omicron

People who get a booster Pfizer COVID-19 vaccine or who had their second jab within six months should be highly protected against Omicron, Israeli health chiefs claim.

Without citing any data, Health minister Nitzan Horowitz said on Tuesday that there was 'room for optimism' based on 'initial indications'.

Just hours later, a report by an Israeli news channel claimed the Pfizer jab was 90 per cent effective at preventing symptomatic infection from Omicron, just slightly less than Delta.

Channel 12 also claimed the super mutant is just 1.3 times more infectious than the dominant Delta variant — much lower than initially feared.  

The news comes after two new cases of Omicron variant were identified in Israel, bringing the total to four. The country closed its borders to foreigners at midnight on Sunday to stem the spread of the new strain.

Mr Horowitz told local reporters on Tuesday: 'In the coming days we will have more accurate information about the efficacy of the vaccine against Omicron.

'But there is already room for optimism, and there are initial indications that those who are vaccinated with a vaccine still valid or with a booster, will also be protected from this variant.'  

A spokesperson for the Health Ministry last night said it was not yet in possession of the data published by Channel 12.  

But the comments come after the co-founder of BioNTech - which developed the Pfizer jab - said he was confident it would hold up against Omicron. 

Sounding an optimistic tone, Mr Horowitz insisted that Israel would not be going into lockdown over the new variant.

'We will not close the country and will maintain life as normal as possible... There is currently no intention to impose restrictions on life within Israel, and we will do everything possible to ensure that this continues.' 

While it is unclear what data is giving the Israeli officials optimism, scientists around the world are conducting lab tests to gauge how worrying the Omicron variant is.

These involve taking a piece of the virus and exposing it to the blood of someone who has been double-vaccinated or boosted, and seeing if the virus can be neutralised. 

BioNTech's Dr Ugur Sahin admitted on Tuesday that the variant will probably cause breakthrough infections at a higher rate than Delta.

However, he claimed that once in the body, the variant will likely be neutralised by the immune systems of double-vaccinated or boosted patients.

'Don't freak out, the plan remains the same: Speed up the administration of a third booster shot,' Dr Sahin told the Wall Street Journal.

He explained that the Pfizer jab provides people with two levels of protection from the virus.

First, it generates Covid antibodies that helps a person's immune system prevent the virus from infecting cells if a person is exposed.

This first layer is focused on the virus's spike protein, which attaches itself to cells and infects them.

Omicron has more than 30 mutations on its spike protein, giving it the ability to evade the first layer of protection.

Protection from the infection is also found to wane over time, as antibodies provided by the vaccine diminish, making a fully vaccinated person more vulnerable to a breakthrough infection.

The second layer of protection remains strong against the variant, though.

After infection, a second wave of protection arrives, as immune cells in the body work to destroy infected cells.

The BioNTech chief does not believe that the variant can evade this second level of protection.

'If a virus achieves immune escape, it achieves it against antibodies, but there is the second level of immune response that protects from severe disease - the T-cells,' he said.

'Even as an escape variant, the virus will hardly be able to completely evade the T-cells.'

The two new cases of Omicron in Israel are doctors who work at the Sheba Medical Center, both of which are also fully vaccinated, The Jerusalem Post reports.

One of the doctors contracted the virus while at a medical conference in London, but had tested negative before boarding a plane home to Israel.

However, a few days later he was tested again, which showed positive, and the results were sequenced to show he had the new variant.

The doctor notified health officials he had come in contact with another doctor at, a cardiologist in his 70s, who has also tested positive for the Omicron variant.

Both doctors were fully vaccinated with three shots of the Pfizer coronavirus vaccine.

'The vaccine is really crucial right now,' Horowitz said on Tuesday. 'Anyone who is exposed to the variant without a vaccine will put themselves at unnecessary risk.'

The news from Israel comes the same day as a report from Israel's Channel 12 news station that said the Pfizer vaccine is 90 percent effective against Omicron, while it was 95 percent effective against the Delta variant.

However, the report notes that Pfizer is 93 percent effective eat preventing serious among those who are fully vaccinated and received a booster.  

According to the report, Omicron's ability to infect people is 1.3 time higher than what was seen in the Delta - but symptoms are less severe. 

At the same time, those not vaccinated have a 2.4 times greater chance of developing serious symptoms, a significant figure.   

South African doctors, who first identified the new variant, said the  strain appears to cause less severe symptoms.

Medics in South Africa said the strain is causing mild symptoms — such as a headache and tiredness — than previous versions of the virus and hasn't led to a single hospitalization or death.

On Monday, Professor Karl Lauterbach, a clinical epidemiologist who is in the running to be Germany's next health minister, said the early reports means Omicron could be a Christmas gift and may even speed up the end of the pandemic.

He suggested that it has so many mutations — 32 on the spike protein alone, twice as many as Delta — which could mean it is optimized to infect and be less lethal, in line with how most respiratory viruses evolve. 

This article has been adapted from its original source.

© Associated Newspapers Ltd.

You may also like