Coronavirus Immunity May Disappear within Months: Study

Patients who recovered from coronavirus infections may lose their immunity to re-infection within months, according to research published on Monday that experts said they could have a "significant" effect on how governments handle the pandemic.

In the first analysis of its type, a team headed by researchers at King's College London looked at the rates of antibodies in more than 90 confirmed virus patients and how they evolved with time.

Blood testing revealed that only people with minor signs of Covid-19 have some immune reaction to the infection.

Of the study group, 60% showed a "potent" viral response in the first few weeks after infection. 

However, after three months, only 16.7% of patients maintained high levels of Covid-19 neutralizing antibodies, and after 90 days, several patients had no detectable antibodies in their bloodstream.

When the body encounters an external danger, such as a virus, it mobilizes cells to track down and kill the alleged culprit.

As it does so, it produces proteins known as antibodies that are programmed to target the specific antigen the body is fighting, like a key cut for a particular lock.

As long as someone has enough antibodies, they will be able to snub out new infections, giving them immunity. 

But Monday's research suggests immunity cannot be taken for granted and may not last more than a few months, as is true with other viruses such as influenza.

Playing the lottery

Experts said the findings may change how governments plan for the next phase of the pandemic, including how they fund and organize vaccine research and development. 

"This is an important study that starts to define the longer-term dynamics of the antibody response to SARS-CoV-2," said Lawrence Young, professor of Molecular Oncology at the University of Warwick, using the full name of the virus strain.

"It further emphasises the need for us to better understand what a protective immune response looks like if we are to develop an effective vaccine," said Young, who was not involved in the research.

James Gill, Honorary Clinical Lecturer at Warwick Medical School, said the research reiterated the need for everybody to continue taking steps to minimize the spread of the virus, especially at the start of Europe's holiday season.

"In the same way that these patients were surprised to have antibodies to Covid-19, we should NOT be surprised if any protective benefit is mild, or at least transient," he said.

"If you played the lottery and won £10, you wouldn't immediately think that you had acquired increased natural luck, and used your life savings to buy further lottery tickets.

"Even those with a positive antibody test -- especially those who cannot account for where they may have been exposed -- should continue to use caution, social distancing and appropriate mask use."

Source: AFP