Reinfection means a person once infected and recovered from the SARS-CoV2 virus -- the virus that causes Covid-19 -- gets infected again, according to the US Centers for Disease  Control and Prevention. As is the case with other viruses, a case of reinfection cannot be ruled out, the agency had noted. 

If a person gets infected and recovers, the "natural infection immune response" can last for nearly six months, says the World Health Organisation (WHO). However, the "protection may not be lifelong",  hence, vaccination is important. 

"Emergence of the second wave of Covid in the country also raises questions about longevity of sustained immunity post Covid infection. Hence, it is advisable to take vaccine for people who were earlier  diagnosed with Covid," Dr Harshal R Salve, Associate Professor at the Centre for Community Medicine, AIIMS in New Delhi, told IANS. 

Covid reinfection cases have been very rare in India. 

According to a recent study conducted by the Indian Council of Medical Research (ICMR), nearly 4.5 per cent cases have been reported as reinfections. The study, forthcoming in the journal Epidemiology  and Infection, examined 1,300 individuals who tested positive for the virus twice. Of these, only 58 or 4.5 per cent, were found as possible reinfections. 

Another study, led by the University of Oxford in the UK, showed that people who once contracted Covid are "highly unlikely" to contract the disease again for at least six months. 

"Covid survivors can get the vaccine but this can be delayed for at least three months after recovering as the immunity last for 3-6 months. Later, vaccination is indicated for protection as well in  case it happens for decreasing the severity, in case Covid happens," Neha Gupta, Infectious Diseases Specialist at Medanta-The Medicity, Gurgaon told IANS. 

People with co-morbidities can be more at a risk than the general population, revealed a recent study by PGI, Chandigarh. It showed that people suffering from Type 2 diabetes and those with the metabolic  disease having no sufficient antibodies or low immunity levels after the first infection are at a greater risk of reinfection. 

Globally, very few cases of reinfection have been confirmed. The first case was reported from Hong Kong in August 2020, where a 33-year-old man reportedly tested positive first in late March 2020.  After making a full recovery with negative viral tests, he tested positive again for while travelling in mid-August. 

A couple of cases from the United States, Belgium, Israel and Ecuador were also reported. 

India' daily Covid-19 tally is now the highest in the world, surpassing Brazil and the US, as it recorded over one lakh cases in the last 24 hours. 

India has also become the second country in the world, after the US, to add more than 1,00,000 cases in a single day at any time during the pandemic. 

The country launched a nationwide vaccination drive in mid-January with the Oxford-AstraZeneca Covishield and Bharat Biotech Covaxin. 

So far, 79,105,163 people have been vaccinated across the country. 

The best way to prevent Covid infection, is to protect oneself by wearing a mask in public places, staying at least six feet away from other people, washing hands regularly and avoiding crowded spaces.