A COVID-19 vaccine specifically targeting the Omicron variant would be "prudent", even if it ultimately may not be needed, the top US infectious disease official said, as Pfizer announced trials for such a vaccine.
On Tuesday, local time, Pfizer and partner BioNTech said they had started clinical trials for a version of their vaccine targeting the highly-transmissible variant.
The companies plan to test the immune response generated by the Omicron-based vaccine both as three-shots in unvaccinated people and as a booster shot for people who already received two doses of their original vaccine.
They are also testing the original vaccine against the Omicron-based vaccine as a fourth dose booster.
Dr Anthony Fauci, President Joe Biden's top medical adviser and a member of the White House COVID-19 Response Team, told MSNBC it made sense have an Omicron-specific booster ready.
"We may not need it … but I think it's prudent to at least prepare for the possibility that this may be a persistent variant that we may have to face — even if it's at a very low level," Dr Fauci added.
While much of the US is still grappling with high Omicron infections, even as cases subside in some states, Dr Fauci said, eventually, enough community immunity would, hopefully, build up to prevent massive surges such as the four to five waves driven by variants so far.
"I don't think we're going to be seeing that indefinitely," he said, adding that COVID-19 was unlikely to be eradicated.
Omicron vaccine needed if 'protection wanes'
Pfizer and BioNTech plan to study the safety and tolerability of the shots in the more than 1,400 people who will be enrolled in the trial.
In a statement, Kathrin Jansen, Pfizer's head of vaccine research and development, explained why the research was being conducted.
Pfizer has said that two doses of the original vaccine may not be sufficient to protect against infection from the Omicron variant, and that protection against hospitalisations and deaths may be waning.
Still, the US Centres for Disease Control and Prevention says a third dose of an mRNA vaccine such as the Pfizer/BioNTech vaccine had provided 90 per cent protection against hospitalisation due to COVID-19.
Some countries have already started offering additional booster doses, but a recent study from Israel showed that while a fourth dose of an mRNA vaccine boosted antibodies, the level was not high enough to prevent infection by the Omicron variant.
BioNTech said it may not be possible to launch an Omicron-specific vaccine by the end of March, as planned, depending on the amount of clinical trial data required by regulators.
Chief executive Ugur Sahin told Reuters in November that regulators would likely not require testing of an Omicron-based vaccine on humans because it and Pfizer had already created versions of their vaccine to target the earlier Alpha and Delta variants, with clinical trials continuing.
However, on Friday, the European Medicines Agency (EMA) said that international regulators now preferred clinical studies to be carried out before approval of a new vaccine.
These studies should show that neutralising antibodies in the blood of participants are superior to those elicited by current vaccines.
Another desired feature of an upgraded vaccine would be for it to also protect against other variants of concern, the EMA said.
BioNTech declined to comment on what type of data it was asked to file with regulators.
It said an analysis of antibodies elicited by its Omicron-targeted booster should help answer whether shots will be needed that address more than one variant at a time.
It hopes to show the antibodies neutralise a spectrum of variants.
"If this is the case, a mix would not be required," it said, adding that it was generating more data to shed light on the issue.
The European drugs regulator has urged pharmaceutical companies to work on more than one upgraded Omicron shot, including versions that address a combination of variants.
The Omicron variant has replaced the Delta variant as the dominant lineage in many parts of the world and Omicron itself is now splitting into different subforms, one of which, BA2, is causing particular concern.
Reuters
