A team of scientists from the Indian Council of Medical Research (ICMR) has conducted a study focusing on potential reinfection cases of COVID-19. The team analyzed 1,300 subjects who had tested positive for the virus twice, discovering that approximately 4.5% or 58 individuals could potentially be classified as having been reinfected.
Worldwide Cases of Reinfection
The first confirmed case of reinfection was reported in Hong Kong, with some additional cases emerging in the United States and Belgium. Although there are several instances of repeated positive testing worldwide, including in India, not all these instances can be classified as reinfections. Experts attribute such scenarios to what is known as “persistent viral shedding.”
Understanding Persistent Viral Shedding
Persistent viral shedding occurs when a person infected by a respiratory virus like SARS-CoV-2 continues to carry low levels of the virus within their system for up to three months post-recovery. While these viral levels are not sufficient to sicken the individual or transmit the disease, they can be detected in diagnostic tests, resulting in consistent positive test results.
Significance of Studying Reinfection
It’s essential to ascertain whether a person who has been infected once develops permanent immunity against the disease, or if they can get reinfected after some time. This understanding is crucial in the fight against the COVID-19 pandemic. It will guide intervention strategies required to control the disease spread, assess reliance on masks and physical distancing, and have implications on the vaccination drive.
Determination of Reinfection
For definitive proof of reinfection, genome sequence analysis of the virus sample is performed. As the virus continuously mutates, the two samples’ genome sequences would present differences. However, since virus samples from every infected person are not collected for genome analysis, scientists from ICMR used an alternative approach, looking at cases wherein patients showed positive results with a minimum gap of 102 days.
Symptoms in Reinfection
Majority of the subjects under study remained asymptomatic during the intervening period. However, a few reported experiencing mild symptoms such as intermittent fever, cough, or shortness of breath.
Implications of Reinfection
Scientists assert that permanent immunity should not be assumed given the potential for reinfections. If reinfections are proven, precautionary measures such as mask-wearing and social distancing could become a prolonged norm.
About Indian Council of Medical Research (ICMR)
The ICMR is India’s leading body for the formulation, coordination, and promotion of biomedical research. It operates under the mandate to conduct, coordinate, and implement medical research benefitting society. This includes the translation of medical innovations into products/processes and their introduction into the public health system. The organization receives its funding from the Government of India through the Department of Health Research, Ministry of Health & Family Welfare.
Last Modified: February 11, 2024