A new study has revealed that COVID-19 antibodies fade after only a month, which could be a devastating blow in the global race to find a vaccine
The study, which was published in PLOS Pathogens, suggested the antibody response in patients who have recovered from coronavirus is not typically strong and declines around one month after patients are discharged from hospital.
In the absence of a vaccine, a better understanding of antibody responses against Sars-CoV-2, the virus that causes Covid-19, is needed to provide key information for developing effective treatments and a potentially a vaccine.
The study involved scientists from Nanjing University Medical School in China, monitoring 19 non-severe and seven severe COVID-19 patients and their Sars-CoV-2-specific antibody responses for seven weeks from the disease onset.
Although 80.7% of recovered COVID-19 patients had varying levels of antibody neutralisation activity against Sars-CoV-2, only a small percentage provided a potent level of neutralisation activity. Furthermore, antibody levels in patients declined significantly between three and four weeks later.
It is not yet known if patients would be susceptible to re-infection.
Using antibodies for other infected patients
This significant decline in antibodies highlights the importance of carefully selecting blood samples from recovered patients using antibody neutralisation assays which could be transfused into other COVID-19 patients.
A British Society for Immunology spokesperson, Professor Danny Altmann, said: “Studies like this are a vital part of the ‘work-in-progress’ to make sense of who has immunity and how long for,
“After the initial publications about Sars-CoV-2 antibody assays and levels, important papers are starting to emerge which look at specificity and durability of the response in more detail.”
The authors from Nanjing University Medical School, added: “The world is facing an unprecedented challenge with communities and economies affected by the growing pandemic of coronavirus disease 2019.
“The development of antibody response to Sars-CoV-2, the virus that causes COVID-19, started to be reported but remained largely elusive.”
Professor Altman commented: “This paper makes a number of points: the gold-standard in assessing the antibody response to a virus is measuring ability to neutralise the entry of virus into cells, although this is not one of the routinely available tests.
“Most convalescent patients show this response, though, importantly, 20% do not. Also, this antibody level declines in most people by the time of their follow-up appointment a month later.
“Once again, evidence shows that the half-life of these antibodies in the blood is not particularly sustained.
“We don’t know to what extent this is bad news unless we know the extent to which the white blood cells that make the antibody (B cells) are up and ready to defend against any repeat attack.”