How long do Covid antibodies last? Immunity after coronavirus infection explained

UK study looked into how much protection the human body produces after natural Covid infection

Since the pandemic began scientific and medical minds have discussed how much protection the body generates against Covid-19 after infection.

Antibodies - the immune system's main defence against Covid - have long been recognised as the primary factor in the fight to defeat the deadly virus.

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There has been much talk around levels of protection, how long protection lasts and if someone can be infected by coronavirus more than once.

UK study looked into how much protection the human body produces after natural Covid infection. (Pic: Shutterstock)UK study looked into how much protection the human body produces after natural Covid infection. (Pic: Shutterstock)
UK study looked into how much protection the human body produces after natural Covid infection. (Pic: Shutterstock)
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Research completed by UK Biobank, the UK's major biomedical database and research resource, may offer the first answers to some of those questions.

How long do Covid antibodies last after infection?

The study undertaken by UK Biobank showed that coronavirus antibodies last for at least six months after infection for the majority who have had the virus.

From 20,200 participants, research showed that 88% of those taking part who had tested positive for previous infection retained coronavirus antibodies for at least six months.

The figure is increased to 99% of participants in the three months after infection, leading to researchers to suggest there is a degree of protection following natural infection.

Professor Naomi Allen, UK Biobank chief scientist, said: “This important study has revealed that the vast majority of people retain detectable antibodies for at least six months after infection with the coronavirus.

“Although we cannot be certain how this relates to immunity, the results suggest that people may be protected against subsequent infection for at least six months following natural infection.

“More prolonged follow-up will allow us to determine how long such protection is likely to last.”

Is the delay between first and second Covid jabs safe?

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Professor Sir Rory Collins, UK Biobank principal investigator and chief executive and British Heart Foundation professor of medicine and epidemiology at the University of Oxford, said: “The fact that infection is producing antibody response that lasts a long time, and as we’ve seen in other studies, is protecting against reinfection does support the government’s decision to delay the second dose.

“And the evidence that they have from the antibody studies that were done with vaccines I think supports the delay, which then allows first doses to be given to very large numbers of people, which was part of the rationale for the government.”

How much of the UK population has had Covid?

The research also found that 8.8% of the UK population had been infected by December 2020 - a figure which rose as high as 12.4% in London and as low as 5.5% in Scotland.

Younger people under the age of 30 reported the highest rates of detectable antibodies (13.5%) and the lowest age group was the over-70s (6.7%). There was no difference in gender.

The seroprevalence of Sars-CoV-2 was highest among participants of black ethnicity (16.3%) and lowest among those of white (8.5%) and Chinese ethnicities (7.5%).

What is the most common symptom of having Covid?

The main symptoms of coronavirus include having a high temperature, a new and continuous cough or a loss or change to sense of smell or taste.

The study found that the most common symptom associated with having Covid antibodies was a loss of sense of smell or taste, reported by 43% of sero-positive participants.

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It also revealed that 40% of sero-positive participants didn't have one of the three main symptoms and 24% were completely asymptomatic.

What does this mean for Covid transmission?

The study was centred around the antibody response a person has to Covid after infection and researchers warned there was more to do to understand the transmission of the virus.

Professor Sir Rory Collins said: “Both with vaccines and indeed with past infection, we don’t yet know what impact that has on the ability to be carrying the virus and transmitting to others.

“So I think one important message both for people who have been infected, and for people being vaccinated, is you may be protected, to some extent, but you may still put others at risk.

“So it’s important to maintain the social distancing and the lockdown measures in line with the Government guidance.”