While two doses of the Pfizer/BioNTech vaccine showed an almost 41-fold decline in protection against the Omicron variant of SARS-CoV-2, the virus that causes COVID-19, the results of the first laboratory experiments on new variant have been hailed as “better than expected”.
Amid a scramble from drug manufacturers such as Pfizer and partner BioNTech, Moderna, Johnson & Johnson and others to produce data showing how their vaccines hold up against the new coronavirus variant, results from a small study led by virologist Alex Sigal, a professor at the Africa Health Research Institute, in South Africa, suggest promising implications for booster jabs.
A “very large drop” in immunity against the Omicron variant with its many mutations was registered among individuals given the Pfizer inoculation, according to the manuscript of the study posted on the lab’s website.
Despite the 41-fold decline in levels of neutralising antibodies against the Omicron variant stated in the study, which has yet to be peer reviewed, “previous infection, followed by vaccination or booster is likely to increase the neutralisation level and likely confer protection from severe disease in omicron infection”.
Sigal’s laboratory studied the blood samples of 12 people vaccinated with the jab, and in five out of six cases those who had been vaccinated as well as previously infected with COVID-19 still neutralised the Omicron variant. The research head of the laboratory at the Africa Health Research Institute hailed the results on Twitter on Tuesday, saying that they showed the “more antibodies you got, the more chance you'll be protected from Omicron."
Furthermore, other parts of the immune system, such as T-Cells, could also work against the virus. The lab had not yet tested the Omicron variant against blood from people who had received a booster dose, as the latter are not yet available in South Africa. Omicron’s “much more extensive escape” from vaccines is estimated to be between five and 10 times greater than that of the Beta variant, similarly first reported in South Africa.
The study also suggested that the omicron variant of the virus uses the same protein - the ACE2 receptor - to bind with human cells. Since this is what the current vaccines are trained to target, Prof Sigal wrote on Twitter that the results were “better than I expected of omicron.” He emphasized that the fact it “needs the ACE2 receptor and that escape is incomplete means it’s a tractable problem with the tools [we’ve] got.”
According to Sigal, Omicron is likely to display an immune escape and transmission advantage over other variants of the coronavirus. The scientist added that the data accumulated in the study is very preliminary with the numbers subject to change.
Last week, BioNTech CEO Ugur Sahin was quoted by NBC News as saying that "we think it's likely that people will have substantial protection against severe disease caused by Omicron.” He added the drugmaker intended to release data related to the new variant on Wednesday or Thursday.
The new research comes as some immunologists have expressed fears that the currently existing vaccines may have little to no impact against Omicron. While the small-scale study might appear promising for booster vaccination programmes, more studies on larger numbers of people will be needed to confirm the results. In the UK, Professor Danny Altmann, an immunologist at Imperial College London, responded to the results of the study by urging those eligible to receive booster doses.
As of Tuesday, a total of 437 cases of Omicron have been identified across the UK: 333 in England, 99 in Scotland, and five in Wales. There is still no clarity regarding Omicron's ability to cause severe disease. The Omicron variant (B.1.1.529), first detected in southern Africa last month, was classified by the World Health Organisation (WHO) on 26 November as a "variant of concern." However, it was added that there was no evidence to support the need for new vaccines specifically tasked with tackling Omicron., and current PCR tests were still successful in detecting the variant.
The Omicron variant of coronavirus is now conformed to have spread to 51 countries on all six inhabited continents, prompting global travel restrictions and fresh vaccine mandates.