On Sunday, the number of people infected with the novel coronavirus in India crossed the 1,000 mark. There are 40 countries who have more people infected. The death toll in India reached 27; the count is higher in 30 other countries.

These numbers would suggest that India is in a relatively better, even if still difficult, situation. But this is not so simple. There are scientists who are saying that over the next two months, the number of infected people in India could cross a million. There are others who assert that community transmission of the virus must already be happening, and these are not getting captured because India has not been testing enough number of people. The Indian Council of Medical Research (ICMR) has been maintaining that despite the emergence of a few cases for which the original source of infection has not been traced, there is no community transmission happening.

Then, there are research papers suggesting that the survivability of the virus weakens in high temperatures, and some have used this to explain the relatively low infection rate in India. In the midst of all this, an unexpected humanitarian crisis in the form of desperate movement of migrant labourers threatens to undo the benefits of the largest-ever lockdown imposed anywhere in the world.

The Indian Express spoke to several scientists and experts to understand how these disparate, some of them conflicting, elements explain the current health crisis. The picture that emerges is still not complete, but it does indicate how these elements are joined together. And this is how it looks like.

Let’s begin with the most important question: How will this end? When a new virus outbreak happens, there are three predictable scenarios through which its spread can be contained.

BLOCK AT SOURCE: In this scenario, every source of the transmission is isolated. In the context of the spread in India, for example, this would have meant identifying and isolating every incoming foreign traveller carrying the virus to ensure that they did not pass on the infection. It is almost certain that this has not happened. Otherwise, the daily detection of new positive cases would have at least slowed down, if not stopped, a week after all incoming flights were stopped. That has not been the case.

COMMUNITY TRANSMISSION: This when the virus gets into the community and infects a substantial fraction of the population. The more vulnerable in the population die of the infection. But in the process, the population develops an immunity to the virus, after which the infections slow down, and eventually the virus is rendered ineffective. This is the principle of herd immunity. This situation becomes more or less inevitable once community transmission begins. The size of the population that gets infected before immunity is developed depends on many factors, notably on how fast the disease is spreading (how many people are infected on an average by every infected person). This entire process can normally take six months to a year. As of now, scientists do not know how long this period could be in case of SARS-CoV2. In any case, this process can be very painful, depending on how lethal the virus is.

VACCINE: This is the situation in which a vaccine is developed, and administered to every vulnerable person. By all accounts, we are at least 12-18 months away from developing a vaccine for SARS-CoV2. By that time, the herd immunity scenario would have played itself out.

Indian express