COVID-19 immunity 'could last three months after infection or vaccination'
The government's scientific advisers say the low numbers being reinfected suggests "natural immunity is sustained in most cases".
Friday 4 December 2020 20:58, UK
People who receive a COVID-19 vaccination may have immunity for 90 days, the government鈥檚 scientific advisers have said.
In a paper considered by the Scientific Advisory Group for Emergencies (SAGE), which also looked into the much-discussed concept of immunity certificates, the experts say that the length of immunity from "natural infection or vaccination is currently not known".
However, they say that "waning immunity" is believed to partly cause other coronaviruses to reinfect after one to two years.
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Meanwhile, seasonal coronaviruses frequently re-infect people 12 months later and sometimes as early as six months on, the scientists say.
"We conservatively estimate that a protective immune response after SARS-CoV-2 infection or vaccination may last for 90 days (moderate confidence)," they say.
"Based on this information, we conclude that: Within one month of natural infection, a high proportion of people will develop immunity which is protective against disease caused by reinfection (high confidence).
"This protection is likely to persist for at least three months (moderate confidence)."
But they add: "Some individuals will not develop immunity following either natural infection or vaccination (high confidence).
"The proportion is unknown but it likely to be small (moderate confidence)."
The paper - which was published on Friday - was produced by the New and Emerging Respiratory Virus Threats Advisory Group (NERVTAG) and considered by SAGE on 19 November.
The low number of confirmed cases of people being reinfected with COVID-19 suggests that "natural immunity is sustained in most cases", NERVTAG says.
According to the document, coronavirus antibodies can be detected in at least 90% of people who have been infected with the virus, while new tests suggest the figure "approaches 100%".
The antibodies can be measured within about a week of symptoms developing, peaking after about one month before declining to a "quite stable level which shows little evidence of further decline over five or six months", the paper adds.
The findings were revealed in a paper that considered the concept of immunity certificates.
This is the proposal to give people who have recovered from coronavirus, or have been vaccinated, "an exemption from current non-pharmaceutical interventions designed to control the spread of SARS-CoV-2", according to the document.
NERVTAG said a "significant number of people who have been infected… may have some 'immunity' that protects them during subsequent exposure".
Meanwhile, the trials of coronavirus vaccines "suggest that a high degree of immunity to COVID-19 disease can be obtained, at least in the short-term", it added.
The experts conclude: "Some form of COVID-19 immunity certification is likely to be possible but further data and considerations are needed before a recommendation can be made."
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The new vaccines minister Nadhim Zahawi revealed this week that the government was looking at issuing "immunity passports" and suggested bars and cinemas "will probably also use that system".
But cabinet minister Michael Gove later ruled out the suggestion, insisting there was no plan to introduce any form of special identification for those who get the jab.
"I certainly am not planning to introduce any vaccine passports, and I don't know anyone else in government who is," he told Sky News.
Matt Hancock revealed in April that the government was considering issuing immunity certificates to those who have recovered from coronavirus.
At the time, the health secretary said the proposal could eventually help people "get back, as much as possible, to normal life", but he warned that further research was still necessary.