Coronavirus: Separating facts from hype

Is Coronavirus the most infectious virus ever?

No, far from it. The infectiousness of a virus depends on the number of people that it spreads to. For coronavirus, it is estimated that one infected person infects about 2-3 other persons. A person with polio would infect about 7 others. A child with measles infection infects 12-15 other children. So, measles is 5 to 7 times more infectious.

Is this the most lethal virus ever?

No, far from it. Lethality is the percentage of people who die from among those infected. In the recent Ebola virus outbreak, for example, lethality was 25-90%. Coronavirus has a lethality of 0.9-3%. It is also less lethal than other new virus epidemics in the last two decades such as SARS and MERS.

We say that the virus spreads through air. Then why are we advised to wash hands to prevent the disease?

It is correct that virus spreads through air. When an infected person breathes out or coughs or sneezes, viruses are released into the surrounding air. They would normally remain in the surrounding air, up to a meter or two from the infected person. When others in the vicinity then inhale, they could also inhale the viruses and get infected. Staying more than one meter away from the infected person reduces the chance of contracting the virus from air.

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However, the viruses also settle down on the surrounding surfaces. When we touch these surfaces, and then touch our face or nose, the virus enters the respiratory system. Washing hands would remove the viruses from hands. It was seen that in the SARS epidemic, handwashing reduced the risk of infection by 55%.

Some people wear masks, and some others do not. Does the mask prevent transmission?

A systematic review of studies conducted during SARS epidemics did not find any clear evidence that surgical masks are effective in preventing infection among community members. Masks, in conjunction with other measures, are helpful for preventing infections among healthcare providers.

If one has coronavirus, what is the chance that the person will become seriously ill? What are the chances that the person will die?

This infection is only 3-4 months old, the information we have is from those infected so far. What we know is that of those infected with coronavirus, about half will remain without any symptoms. They are simply carriers of infection without any signs and symptoms.

About 90% would have mild illness that is-- cough, fever, sore throat, etc., for a period of 7-14 days. About 5-10% would have severe disease that affects the lungs and will require hospitalization. About 1-3% will die.However, the chances of getting ill and dying differ widely with age. For example, from the data from China and early epidemic in Europe, for the age group 20-40 years, chances of dying were 0.05% (about 1 in 2,000) and for those above 70 years of age, it is about 8% or about 1 in 12. In Italy, the average age at death has been 80 years, and the median age at infection about 62 years.

We are also juxtaposing the risk of dying due to some other causes in US and India for you to make sense of these numbers: 1 in 800 women in India die due to childbirth; 1 in 111 persons in the US who suffer a fall die; 1 in 6 persons in the US who have heart disease die.

Will all seriously ill patients require ventilator care?

No, based on the analysis of first 160,000 patients, about 70% of all those who are ill enough to require hospitalization would require supportive care and oxygen alone. Most of them can be saved. The remaining 30% will require ventilator care. Among those who require ventilator care, about 50% would die in the best of situations.

Are the transmission rates in India lower or higher than those in other countries?

We do not know for sure. India has tested much fewer cases than other counties: for example, 26,798 cases as compared to UK’s 1,20,776 till March 28, and that makes comparison difficult. However, based on the number of tests performed so far, India has much lesser positivity rate than other countries. It does suggest that the transmission in India may be lower than in other countries.

(Dr Pavitra Mohan, earlier of the child health and health systems portfolio at UNICEF India, is a paediatrician, public health expert and co-founder of Basic Healthcare Services (BHS). Arpita Amin, a public health professional, is a Research Executive with BHS) (Through The Billion Press)