Will current vaccines work against Omicron? – Expert Reaction

Current vaccines may not work as well against the Omicron variant than for earlier strains of the coronavirus, according to recent comments made by Moderna’s chief executive.

The Financial Times reported on comments made by Stéphane Bancel questioning the effectiveness of COVID-19 vaccines against the Omicron variant of SARS-CoV-2.

The SMC asked experts to comment on the news.

Dr John Taylor, Senior Lecturer in Virology, School of Biological Sciences, University of Auckland, comments:

“It is still very early days regarding omicron and while there’s lots of sensible speculation, there is no hard data that establishes whether this variant is more transmissible, more virulent or can evade immunity acquired from previous infection or vaccination.

“Moderna’s CEO is probably correct to predict that data will soon emerge to show omicron has increased ability to evade vaccine-induced immunity. Based on what we know about the structure of the virus spike protein and the biology of antibody neutralisation, the large number of mutations in the omicron spike make this a likely outcome. We will know in the next few days as neutralisation studies are completed.

“Right now, there are probably hundreds of labs around the world racing to make copies of the omicron spike gene that will allow them to create a surrogate form of the virus that can be used to measure how well vaccines work against the new variant.

“But if this is found to be the case it doesn’t mean the current vaccine is not effective because protective immunity doesn’t just come from having a high concentration of antibodies in the blood that can neutralise the virus by binding to its spike protein.”

No conflict of interest

The UK Science Media Centre has also gathered comments in response to these comments.

Prof Eleanor Riley, Professor of Immunology and Infectious Disease, The University of Edinburgh, said:

“The Moderna CEO may well be right in terms of whether the existing vaccines are sufficient to prevent infection per se. But the impact on hospitalisation and death is likely to be much less severe. Immunity to severe disease is mediated by T cells as well as antibodies and these are less susceptible than antibodies to simple mutations.

“But we won’t really know for a few weeks until there are enough cases of omicron infection to see what the hospitalisation rate is and who is being hospitalised (age, vaccination status etc.). This data will likely come first from Southern Africa where the virus seems to be most prevalent currently.

“We can assess in the lab how susceptible omicron is to neutralisation by vaccine-induced antibodies; this correlates very well with how good the antibodies are at preventing infection.  These assays are going on now at the labs at Porton Down and elsewhere. I would expect some initial results in the next few days and that will give us our first real hard data.

“However, there is no lab assay to measure immunity to severe disease; we need to wait for the clinical data.”

No conflicts of interest declared.

Dr Peter English, Retired Consultant in Communicable Disease Control, Former Editor of Vaccines in Practice, past Chair of the BMA Public Health Medicine Committee, said:

“The number of mutations in the omicron virus, compared to the virus used to develop vaccines, suggests that vaccines are unlikely to work as well. We do not yet know how significant a real-world effect this will have.

“We will need to monitor cases (infections without symptoms as far as possible, although this relies on routine testing; symptomatic cases; hospitalisations with Covid-19; ditto critical care admissions, and deaths) in real world populations, and to relate the individual cases to their vaccination status. This will tell us how effective one, two, three, or four (people getting a three-dose “primary” course plus a “booster”) doses are, for different vaccines and vaccine combinations.

“We know that the vaccines have held up pretty well against variants, with only a slight drop in efficacy – particularly of a single dose – against the delta strain. That is somewhat reassuring, but we cannot rely on it.

“It is certainly worthwhile developing and rolling out variant modified vaccines, as a precaution, and because it might improve efficacy against existing, as well as new strains, as they arise.”

Conflict of interest statement: “Dr English is on the editorial board of Vaccines Today: an unpaid, voluntary, position.  While he is also a member of the BMA’s Public Health Medicine Committee (and its chair until Oct 2020), this comment is made in a personal capacity.  Dr English sometimes receives honoraria for acting as a consultant to various vaccine manufacturers, most recently to Seqirus.”