Covid-19 antibodies protect from reinfection for at least nine months, according to a new Chinese study published in The Lancet medical journal.
The study of 9,500 Wuhan residents saw participants tested for antibodies in April 2020, shortly after lockdown was lifted in the city of 11 million, again in June, and for a third time between October and December the same year. The results concluded that of the 6.9 percent of the participants who were found to have Covid-19 antibodies in April, around 40 percent were protected from reinfection for at least nine months.
As with previous studies conducted in other countries, the Chinese researchers found the percentage of the population with antibodies was higher than the official infection rate. They concluded that this was because most people with no or mild symptoms did not get tested. Those with antibodies who did not get tested also had a lower level of antibodies than those who tested positive for Covid-19.
The researchers said the findings underlined the importance of achieving herd immunity in China and would help inform ongoing vaccine development.
On Sunday, health officials appealed to the public to get vaccinated. They admitted, however, that there is no guarantee against infection, so quarantine and prevention rules would still apply.
With the outbreak largely under control in China, many citizens have been reluctant to take the Chinese vaccines, all of which have yet to publish stage three trial data and win approval from the WHO.
As of Saturday, nearly 75 million people had received at least one dose of a Chinese vaccine, according to the National Health Commission. With a population of 1.4 billion, this marks a much lower take-up rate than many foreign countries.
“Many people mistakenly think there is no practical meaning to be vaccinated because the epidemic situation is under effective control and the virus is far away from us,” He Qinghua, a National Health Commission official, said at a press conference.
He added that herd immunity is very low in China because only a small proportion of the population has been infected with the virus.