The Financial Times have reported on comments made by the chief executive of Moderna, Stéphane Bancel, about the effectiveness of COVID-19 vaccines against the omicron variant of SARS-CoV-2.
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.”
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.”
All our previous output on this subject can be seen at this weblink:
Dr Peter English: “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.”
None others received.