The first documented case of reinfection with Covid-19 was reported in a 33-year-old man in Hong Kong almost 4 ½ months after he recovered from his first infection. Closer to home, recently there have been reports of reinfection cases in Bangalore, Delhi and Mumbai, especially amongst healthcare workers. Researchers in India have also reported few cases with asymptomatic reinfection of Covid-19.

WHAT IS COVID-19 REINFECTION?

In simple words, reinfection means that a person was infected once, cleared the infection and then the person was infected again.
Initial evidence suggests that normally, in case of an infection, the COVID Immunoglobulin G (IgG) antibody is tested positive after 2-3 weeks of the infection. However, in certain cases, the antibody tests negative, which means that the person does not develop immunity after infection. Another possibility could be that the antibodies are short-lived and disappear quickly, thereby making the patient susceptible to reinfection. Thus, reinfection cases mean that the antibodies may not be produced by every patient or if they do develop, they may not last long enough, and therefore, allowing the virus to enter the body and cause the disease again.

HOW LONG DOES IMMUNITY LAST?

The immune system's memory is rather like our own - it remembers some infections clearly, but has a habit of forgetting others.
The new coronavirus, Sars-CoV-2, has not been around long enough to know how long immunity lasts.
But a recent study led by Public Health England (PHE) shows most people who have had the virus are protected from catching it again for at least five months (duration of the analysis so far).

WHY DOES IMMUNITY MATTER?

It matters for obvious personal health reasons and whether you will get Covid-19 multiple times and how often.
Immunity will also affect how deadly the virus is. If people retain some, even imperfect, protection then it will make the disease less dangerous.
Understanding immunity better could help ease lockdown if it is clear who is not at risk of catching or spreading the virus.

Now is not the time to give up! So, keep washing your hands, wearing a mask in public places and keep physically distancing when possible.