A NEW study has revealed the UK cannot rely on herd immunity as there is no way to tell if someone is immune - even if they have already had Covid.

Many people may also need "booster vaccines" to protect them against the virus.

The Imperial College London study Covid antibody levels fall “quite rapidly” after coronavirus infection, meaning immunity may not last long and reinfection rates may increase.

What is herd immunity?

Herd immunity is when enough people become resistant to a disease – through vaccination or previous exposure – that it can no longer significantly spread among the rest of the population.

With no vaccine available for Covid-19, herd immunity relies on enough people in the population becoming infected to lessen the impact of the disease.

While Imperial researchers remain optimistic about a vaccine being able to stimulate longer-lasting protection, further doubt has been cast on whether even a degree of herd immunity will be effective.

The Government was slammed for its herd immunity approach back in March and April, but earlier this month top scientists backed the strategy after criticising current lockdowns in the so-called Great Barrington Declaration.

There is no way to tell if you're immune

ITV Good Morning Britain Doctor Hilary Jones today issued a warning on herd immunity following the research.

He urged everyone to follow guidelines, even if they have had Covid, because "we can’t rely on individual or herd immunity".

Mr Jones said: "We’ve got to forget that getting Covid-19 will make us immune going forward. The vaccine is a different story.

"People who have been exposed in the past can’t guarantee that they’re immune. They need to know that they can get reinfected and that they can give the infection to other people."

This does not, however, mean that immunity is not achievable. 

Dr Alexander Edwards, associate professor in biomedical technology at the University of Reading, said the rapid home tests used in the study are generally only “able to detect only high levels of antibody”. 

When a person is sick, antibodies rise and drop then off again when they are better. 

Mr Edwards said: "What is not clear is how quickly antibody levels would rise again if a person encounters the Sars-CoV-2 virus a second time.

“It is possible they will still rapidly respond, and either have a milder illness, or remain protected through immune memory.

“So even if the rapid antibody test is no longer positive, the person may still be protected from re-infection.

“But we don’t know this yet, it takes time to work this out, by following large groups over many months, and this type of study is ongoing yet hard and slow.”