Thanks largely to the social media! Corona pandemic has become the most talked about subject and a cause of panic all over the world. Experts have made variable predictions about the gravity of the current scenario and the possible predictions. Fortunately, we in India have been able to contain the menace within limits with timely and logical steps. But the future keeps on raising doubts about what will happen next.
Mortality, not the number of infected persons is the best epidemiological index of the seriousness of an epidemic. Prevalence of a disease depends upon the numbers tested and method of testing which can be erratic. Mortality does not go unnoticed or under-reported. Fortunately, there has been no report of a rapid increase in usual death-rates. Do not depend upon daily counts of positive tests or numbers of deaths. These are meant for the scientists and the administrators. There has been no exponential or recognizable increase in deaths in India during the last 2-3 months since the disease recognition.
Most net-viewers would have seen the mortality curves from different diseases. Corona virus mortality is significantly lower than those of tuberculosis, swine flu, measles and others. We have learnt to live with them. Take the example of Swine-flu pandemic which affected 700 million to 1.4 billion people and killed over 2 lakhs world-wide while about 50 thousand Indians were affected with about 3000 deaths. Factually our bodies have adapted to around a hundred odd infections. There are high titres of antibodies circulating in blood of Indians. This could be preventive, even if by less than 5 percent.
The number of people to whom an infected individual can pass on the virus on an average is calculated as its reproductive number or R nought which is 2-2.5 for corona virus. This is not very high in comparison to most other infections cited earlier. There is good evidence to say that a 60% of reduction at source would be sufficient to bring down the R from 2-2.5 to below 1. An R of 1 shall significantly flatten the curve. It is possible to achieve this goal with use of barriers such as face masks by infected people and patients. There has been lot of recent work on mass use of masks. While scientific criteria for the types of masks and their use are quite stringent, any barrier over the face even with cloth-masks is adequate to decrease transmission. There is very reasonable filtration power of cloth mask plus reduction of aerosols in cough. Surgical mask is only marginally better than cloth mask for the efficiency for filtration of microbes for a public health intervention. The common Indian practice of covering the face with ‘dupatta’ by women is good to prevent direct droplet spread.
The high environmental temperature and humidity expected to increase soon, is also helpful. High environmental temperature does not kill the virus but helps to reduce the viral transmission and community spread by drying up the droplets. Some degree of immunity is also likely to develop in the community as we progress with the epidemiological curve. There are a few research articles to suggest that the Indian strain has already mutated to a less virulent form. It is certainly a good news, if really be true. Other scientific advances such as development of drugs and vaccines are already in the pipe-line. It may take some months but remain the ray of hope.
There a number of questionable hypotheses and anticipations. There is no doubt that strict vigil is necessary to contain the transmission. The public health interventions undertaken by the government are already showing a positive outcome. The curve shall soon flatten but the momentum must be maintained. But fear must not overcome the hope: “The only thing to fear is the fear itself”.
Dr Surinder K. Jindal, MD, FCCP, FAMS, FNCCP
(Emeritus-Professor, Postgrad Instt Med Edu & Research, Chandigarh, India)
Medical Director, Chandigarh, India 160020