Written By: Longjam Dineshwori | Updated : August 27, 2020 9:23 AM IST
Antibodies in COVID-19 patients may decline within 2-3 months, suggest researchers.
India's COVID-19 tally has crossed 31 lakh and over 58,000 people have lost their lives to this condition so far, according to data on the Union Health Ministry website. But the good news is that the recovery rate is also rising in the country. As per the latest Health Ministry report, the COVID-19 fatality rate has declined to 1.85 percent, while the recovery rate has risen to 75.27 percent. More than 24 lakh people have recovered from the disease in India. Are those who have recovered from COVID-19 and have antibodies protected from a second infection? This is one of the many questions about the novel coronavirus that doctors and researchers have been unable to answer so far.
In what is considered to be the first documented instance of coronavirus reinfection, a Hong Kong man tested positive for COVID-19 again four-and-a-half months after recovering from the disease. This case indicates that the disease may continue to spread amongst the global population despite herd immunity, researchers at the University of Hong Kong said on Monday.
The 33-year-old man, an information technology worker, was cleared of COVID-19 and discharged from a hospital in April. His second SARS-CoV-2 infection was detected via airport screening on his return to Hong Kong from Spain via Britain on Aug. 15.
He was found to be infected by two different coronavirus strains but he didn't show any symptoms from his second infection. This indicates that any "subsequent infections may be milder," the researchers said in a paper, which was accepted by the international medical journal Clinical Infectious Diseases.
Based on their findings, they suggested SARS-CoV-2 may continue to circulate even if patients have acquired immunity via natural infection or via vaccination.
However, the World Health Organization (WHO) epidemiologist Maria Van Kerkhove said that there's no need to jump to any conclusions right now. Studies tracking larger numbers of cases over time are needed to better understand the quality and durability of recovered patients' neutralizing antibody response to SARS-CoV-2, she told reporters in Geneva Monday in response to the Hong Kong case.
While there is no strong evidence yet to prove that recovered COVID-19 patients get reinfected, researchers have found that antibodies against SARS-CoV-2 may start waning after a few months.
A study published in the journal Nature revealed that asymptomatic COVID-19 patients experienced a decline in antibodies within 2-3 months. The study done in China found that levels of Immunoglobulin G (IgG) an antibody that protects against bacterial and viral infections dropped in about 93 percent asymptomatic COVID-19 patients and about 96.8 percent symptomatic people in the early convalescent (recovery) phase. In addition, they found a decline in neutralising antibodies the antibodies that bind to the virus and stop the infection in as many as 81 percent of asymptomatic patients and 62 percent of the symptomatic cases.
Another report from China's Zhongnan Hospital of Wuhan University revealed that 90 per cent of coronavirus-recovered patients admitted in the hospital suffered from lung damage and five per cent of them tested positive for the virus again.
With inputs from news agencies
