A third top-up booster dose of a COVID-19 vaccine provides high levels of protection against severe disease from the Omicron variant among older adults, a latest UK study concluded on 8 December.

The UK Health Security Agency (UKHSA) analysis showed that around three months after the third jab, protection against hospitalisation among those aged 65 and over remains at about 90 per cent. Whilst with a booster shot, the duration of protection against the severe disease remains high, protection against mild symptomatic infection is more short-lived and drops to around 30 per cent by about three months.

The UKHSA study examined booster shots in those aged over 65, who were among the first to be eligible when the UK's booster vaccination rollout began in mid-September 2021. The latest findings also show that protection from getting a severe infection from the Omicron variant of COVID-19 after the first two doses wane within months.

With just two vaccine doses, protection against severe infection drops to around 70 per cent after three months and to 50 per cent after six months, the study noted. The UK's Joint Committee on Vaccination and Immunisation (JCVI) said it has taken this latest evidence into account in its ongoing review of the booster programme and decided against the need for a fourth booster dose rollout at this stage.

The current data shows the booster dose is continuing to provide high levels of protection against severe infections, even for the most vulnerable older age groups. For this reason, the committee has concluded there is no immediate need to introduce a second booster dose, though this will continue to be reviewed, said Professor Wei Shen Lim, the JCVI's chair of COVID-19 immunisation.

The data is highly encouraging and emphasises the value of a booster jab. "With Omicron continuing to spread widely, I encourage everyone to come forward for their booster dose, or if unvaccinated, for their first two doses, to increase their protection against serious illness," he said.

The JCVI has concluded that there is no immediate need to introduce a fourth jab to the most vulnerable groups such as care home residents and those aged over 80 and that priority should continue to be given to rolling out the first booster shots to all age groups. However, extremely vulnerable patients with impaired immune systems are still advised to administer the fourth shot to get fully vaccinated.