Vaccine efficiency has fallen below 90% – JCVI

Professor Wei Shen Lim, of the Joint Committee on Vaccination and Immunisation, said the strategic aim of the COVID vaccine rollout was initially to prevent spread of the disease.

He insisted this has not changed for the booster programme.

Professor Lim said we can only measure levels of protection up to six months after the vaccine is given.

Therefore, we have to project what later efficacy may be.

Professor Lim said data shows over time there is a slight decrease in vaccine effectiveness from a little over 90% to under 90% (see chart below).

This still means there is a “high level of protection”, he said, but there is a suggestion of a decrease.

He added the most marked decrease in protection is in older people and those with underlying health conditions.

Professor Lim said the JCVI took this into account in coming to its advice.

The booster programme will be offered to those who are more vulnerable in order for them to maintain a high level of protection throughout the winter.

This includes: older adults living in residential care homes, frontline health and social care workers, all adults aged over 50, those aged 16 to 49 with underlying health conditions, and adult contacts of the immunosuppressed.