The UK chief medical officers have backed a proposal to temporarily suspend the 15-minute observation period for patients who have received an mRNA Covid jab, given the need to speed up vaccinations in response to the Omicrom variant.

Their view is that “with the low rates of anaphylaxis, in the context of the considerable need for people to be boosted or vaccinated, the 15-minute wait after a vaccination with mRNA vaccine will cause more harm than it can avert because it will significantly reduce the number of people who can be vaccinated over a short period of time”.

The CMOs recommend that the 15-minute wait should be suspended for first, second and homologous or heterologous boost vaccinations with mRNA vaccine given the current situation. Analysis by NHS England indicates that when clinics are working at full capacity the 15-minute wait reduces throughput by 23 per cent.

If ministers agree then the CMOs say this should be a temporary measure on the grounds of public health need to protect as many people as possible over a short period of time. How the 15-minute suspension is operationally implemented should be determined by each nation.

The CMOs recognise that this will lead to a marginal increase in risk for a very small number of people, but say the number will be substantially fewer than would be harmed by a slower vaccine roll-out in the current public health emergency.

Any long-term decision on the 15-minute wait will rest with the Commission on Human Medicines, the Medicines and Healthcare products Regulatory Agency, and the Joint Committee on Vaccination and Immunisation.

The Omicron variant is spreading rapidly, with a doubling of cases every two to three days. Even if it causes less severe illness than Delta, with the very high numbers involved modelling from several groups show this will cause substantial mortality, severe illness and pressure on the NHS, says the Department of Health. “There is therefore a need to boost as much of the population as possible before the peak of the Omicron wave.”

The mRNA vaccines have shown better ability to boost immunity and are therefore the basis for the current booster campaign. In the CovBoost study, antibody responses to mRNA vaccine boost were also much quicker than for other vaccine types - typically seven to 10 days.

For mRNA vaccines there have been two fatal Yellow Card reports of anaphylaxis linked to primary course vaccination and no deaths from anaphylaxis linked to booster vaccination reported in the UK to date.

Within the 15-minute waiting time 17 events have been reported, with a further 14 events being reported outside the 15minute period but within the same day. There were no fatalities, although in 18 cases adrenaline was administered and eight people were hospitalised.