The Johns Hopkins University COVID-19 tracker estimates that over 16 million people worldwide have been infected with the coronavirus that causes COVID-19. It also estimates that nearly 650,000 people have died from the disease, but millions have recovered.
So, a question many people around the world are asking is – can you get it again? In fact, that was among the most-searched questions on Google's website for many weeks in May and June.
Whether or not you can catch COVID-19 again after getting infected once is connected to your body's immune system. Does infection strengthen the body's natural defenses as it does with other pathogens? And if there is an immunity, how long does it last?
Right now, there are no clear answers to these questions.
The U.S. Centers for Disease Control and Prevention and other groups say they do not yet know how the immune system reacts to COVID-19 or SARS-CoV-2 -- the virus that causes the disease. This includes how long the body stays immune to infection from the virus.
MERS-CoV is a similar virus. They are both coronaviruses. Patients with MERS-CoV are unlikely to be re-infected shortly after they recover. It is not yet known whether patients with COVID-19 will have similar protection.
Antibody tests check your blood for antibodies. Experts at the CDC note that such tests may show if you had a past infection with the virus that causes COVID-19.
Antibodies are proteins that fight off infections. They can protect you from getting that disease again. In other words, they give you immunity.
However, antibodies are disease specific. For example, measles antibodies will protect you from measles if you are exposed to the disease again. But those antibodies will not protect you from getting mumps, for example, if you are exposed to mumps.
Back in April, the Reuters news agency reported on the situation in South Korea. Several patients there were said to have recovered from COVID-19 but then later tested positive for the virus.
Experts told Reuters that there were three main possibilities: re-infection, a relapse or inconsistent testing.
A relapse means the virus never really left the patient. Patients think they are better but are not and soon feel sick again.
The worst possibility would be re-infection. This would mean the immune system did not create antibodies to protect it from future infection.
I'm Anna Matteo.