Covid-19 second wave brings focus back on R-factor. This should worry you | Explained - Happy Boss

Happy Boss

Wednesday, 24 March 2021

Covid-19 second wave brings focus back on R-factor. This should worry you | Explained

The second wave of Covid-19 has brought back the focus on the R-factor -- the rate of reproduction of the novel coronavirus infection. Here's all you to know about R0 (pronounced as R-naught) or R-factor.

R-naught in the second wave of Covid-19 pandemic in India is currently 1.32.(Image for representation: File photo)

The rate of vaccination in India is far greater than the spread of coronavirus infection. In little over two months, India has vaccinated far more people with over 5 crore doses than its total Covid-19 caseload. Total Covid-19 cases in the past one year (leaving aside the January cases reported in Kerala among those returning from China) stand at 1.17 crore.

The two figures tell us that herd immunity is is still a long way away in India with a population of about 137 crore. This leaves a huge scope for the spread of Covid-19. And, in its second coming, the coronavirus is spreading Covid-19 at an alarming rate once again.

Reports suggest that the rate of reproduction of coronavirus infection has reached its highest level since March-April 2020. This rate is called R0, pronounced as R-naught. It lets you know how many healthy persons an infected patient can spread the disease to.

R-naught, also called R-factor, in the second wave of Covid-19 pandemic in India is currently 1.32. This means one infected person is passing on the disease, on an average, to 1.32 healthy persons.

It is the highest since March 27-April 6 period last year when it was 1.83. It declined thereafter to 1.23 in second half of April and first half of May. It reduced further to stand at 1.16 in July. India saw a consistent decline of active caseload between September 2020 and February 2021. The R-naught had come down below 1.

HOW TO INTERPRET R-NAUGHT?

Ascertaining R-naught is crucial for policy makers and authorities involved in pandemic control as it tells how fast a virus will spread from an infected person to a population that has never caught the disease — Covid-19 in this case.

If R-naught is over 1, it means the disease is expanding its footprints in newer population groups at an increasing rate.

If R-naught is less than 1, it means the spread of disease is declining, and may peter out over a period of time.

In India, R-naught or basic reproduction rate of Covid-19 pandemic has reversed its curve. No single factor leads to such a reversal in a pandemic situation.

COVID-19 SURGE, R-NAUGHT AND YOU

Experts attribute the second wave of Covid-19 in India to a number of factors including laxity on part of the people in adhering to hygiene protocol such as wearing a mask, maintaining physical distance and hand sanitisation, and arrival or emergence of more virulent mutant variant of the coronavirus.

Not following Covid-19 protocol or exposure to more infectious variant of coronavirus can revive R-naught causing faster spread of the pandemic. However, a reversal of R-naught or a higher R-naught may not necessarily be a worry for people and the authorities.

For example, the seasonal flu usually has an R-naught of 1.3 or more. It infects millions of people every year. This means the incidence of severity of the disease outbreak is a bigger determinant of the seriousness of the health problem.

Another factor is that a higher R-naught does not necessarily tell how fast the disease will actually spread. R-naught refers to the possibility of the rate of spread of the said infection.

If safety protocol such as wearing of a face mask is followed, the rate of spread could be easily checked forcing the R-naught to come down in days. Still, the current rise in R-naught in India is alarming as it tells the general population may have falsely believed that Covid-19 pandemic has been defeated or the country has achieved herd immunity.

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