There is still a lot to learn about coronavirus disease (COVID-19), which is currently ravaging across the globe. Though scientists are slowly gaining a better understanding of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), it is still unclear if being infected once may provide long-lasting immunity against the novel coronavirus.
New cases of reinfection have been reported across the globe. Now, a doctor at Sheba Medical Center in Tel Hashomer, Israel's Largest Hospital, has tested positive for SARS-CoV-2 three months after recovering from the coronavirus disease (COVID-19).
The doctor contracted the virus in April during the height of the pandemic in the country. By May and June, swab tests showed that the doctor has fully recovered from the disease. However, when the doctor was tested again in July, results returned positive.
Novel Coronavirus SARS-CoV-2 This transmission electron microscope image shows SARS-CoV-2, the virus that causes COVID-19, isolated from a patient in the U.S. Virus particles are shown emerging from the surface of cells cultured in the lab. The spikes on the outer edge of the virus particles give coronaviruses their name, crown-like. Image captured and colorized at NIAID's Rocky Mountain Laboratories (RML) in Hamilton, Montana. Credit: NIAID
Testing positive again
A hospital spokesperson said that the doctor tested positive again since she has remnants of her first virus still found in the blood. In her April bout, the doctor experienced fever, cough, and body pains but has since recovered from the illness.
However, in early July, the doctor came in contact with a confirmed case of COVID-19, and after, she tested positive for SARS-CoV-2 again. This case is the latest in a string of incidents of potential reinfection, raising questions on how long immunity against SARS-CoV-2 lasts, or if there is any at all.
Other cases of reinfection
There were reports of recurring coronavirus cases in other countries, including Canada, Japan, South Korea, and the United States. In these countries, some patients who have previously recovered from COVID-19 became infected by the virus again after three months.
The pattern of the reinfection cases raises concern that the antibodies developed by the body against SARS-CoV-2 may not necessarily protect the body from future infections. If the antibodies do provide protection, they may not last for long. Hence, the new information highlights the need for an effective vaccine to provide the needed protection against the novel coronavirus, which has now infected more than 14.63 million people and killed at least 608,000.
Understanding repeat infection risk
Is reinfection possible in people who had been infected with the coronavirus? A study published in May by scientists at Columbia University Mailman School of Public Health found that reinfections with endemic human coronaviruses are not uncommon, even within a year of prior infection. The team studied four other types of coronaviruses.
Also, many studies are attempting to figure out how long the protection provided by antibodies will last. For other coronavirus infections, such as severe acute respiratory syndrome (SARS) and the Middle East respiratory syndrome (MERS), those who recovered had some form of immunity for about a year or longer in others. When it comes to other forms of coronaviruses, which circulate regularly, the immunity period is shorter.
Another recent study also explored how long the immunity against SARS-CoV-2 may last, and found that the antibodies protect about an average of three months. This will make the development of vaccines harder since the vaccines are now being trialed to determine their safety and efficacy. Without a precise immunity period, some vaccines may not work as effectively.
Israel, for one, launched a widespread serological testing or antibody testing to determine the extent of the pandemic. Since there is a reinfection risk and the antibodies fade out in time, governments and authorities should not use an antibody test as a ticket to immunity.
So far, Israel records more than 52,000 confirmed cases of COVID-19 and 415 deaths. Meanwhile, the United States reports the highest number of infections, with a staggering 3.81 million people and more than 140,000 deaths. Other countries with high numbers of confirmed cases include Brazil, with more than 2.1 million cases, and India, with more than 1.11 million.