How effective are Covid vaccines at preventing Omicron infection – regardless of symptoms – and therefore stopping people spreading it?

It is among the most common questions being asked as debate rages around mandatory vaccination for NHS staff from April.

Some believe getting jabbed is vital to protect vulnerable patients, others say full PPE and daily tests achieve that while vaccines do not prevent transmission.

What does the expert say?

Hertfordshire’s director of public health, Jim McManus, said vaccine effectiveness against catching Omicron is “suggested to be in the range of 40-50 per cent”.

“Although vaccines don’t completely stop infection and transmission, they do roughly halve your chances of becoming infected, and therefore the risk of you passing on an infection to someone more vulnerable than you.

“This is true even in people who have already had Covid, as previous infection only provides around 20 per cent protection against the Omicron variant.”

So there we have it – vaccines are around 40 to 50 per cent effective at preventing Omicron infection. But how well do they prevent serious illness?

‘Extremely effective’

Mr McManus said: “Latest data shows that around three months after receiving their booster dose, protection against hospitalisation among those aged 65 or over remains at around 90 per cent. 

“Being double vaccinated will give you similar levels of protection for around three months.”

He added that while younger and healthier people are less likely to need hospital treatment, there are still some who are unvaccinated getting seriously ill and dying.

“No vaccine is completely effective, but it’s clear that the vaccinations and booster doses are making a huge difference to the number of people getting seriously ill and are helping limit cases of this highly infectious Omicron variant.”