Covid-19: What we know and what we don’t

Though the world is tackling coronavirus outbreak at war footing, there is a lot we don’t know about the virus.
A security personnel uses a thermal screening device on visitors at the entry gate of a housing society in Gurugram, on Sunday, as a precautionary measure to check the spread of coronavirus.(Yogendra Kumar/HT Photo)
A security personnel uses a thermal screening device on visitors at the entry gate of a housing society in Gurugram, on Sunday, as a precautionary measure to check the spread of coronavirus.(Yogendra Kumar/HT Photo)
Updated on Mar 09, 2020 01:03 PM IST
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Hindustan Times, New Delhi | By

Since the first case was reported on January 31 of coronavirus disease (Covid-19), with a Kerala student from Wuhan testing positive, India has reported 43 positive cases of the viral disease so far. While information about the virus and the disease so far is limited, in India the disease pattern so far suggests mild infection.

The virus and the disease

Official name was announced for the virus and the disease it causes by the World Health Organisation (WHO). The disease is called coronavirus disease (Covid-19). The virus has been named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

The disease pattern

The global data suggests, in about 80% of the cases the disease is mild, and 15% are severe infection, requiring oxygen, and 5% are critical infections, requiring ventilation. While the true mortality of Covid-19 will take some time to fully understand, the data so far indicate that the crude mortality ratio (the number of reported deaths divided by the reported cases) is between 3-4%. For seasonal influenza, mortality is usually well below 0.1%.

Not influenza

While both viruses cause respiratory illnesses, the speed of transmission is an important point of difference between the two viruses. Influenza has a shorter median incubation period (the time from infection to appearance of symptoms) and a shorter serial interval (the time between successive cases) than Covid-19 virus. The serial interval for Covid-19 virus is estimated to be 5-6 days, while for influenza virus, the serial interval is 3 days, meaning influenza can spread faster.

Children less affected

For Covid-19 virus, initial data indicates that children are less affected than adults and that clinical attack rates in the 0-19 age group are low. Only one case of a three-year-old testing positive to coronavirus has been reported from Kerala. Further preliminary data from household transmission studies in China suggest that children are infected from adults, rather than vice versa.

Who are at high-risk

Those most at risk for severe influenza infection are children, pregnant women, elderly, those with underlying chronic medical conditions and those who are immunosuppressed. For Covid-19, our current understanding is that older age and underlying conditions increase the risk for severe infection.

Cure and prevention

No licensed medicine is available for Covid-19 currently; anti-HIV/AIDS medicine (Lopinavir and Ritonavir) are being given to severely ill patients under restricted use. Several clinical trials are on for drugs, and about 20 vaccines are under development.

What we still don’t know about Covid-19

Origin of the virus: There is still no definitive animal source identified but preliminary research suspects the virus jumping into humans from snakes, rats or bats

Incubation period: How long does it actually take for the virus to show symptoms

Mutability: Whether or not it’s prone to mutations; how fast will it mutate.

Population based behaviour: How will it behave among people of a particular race or region

Cure: There’s no cure for the disease; clinical trials for many possible drugs are on and 20 vaccines are in development

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  • ABOUT THE AUTHOR

    Rhythma Kaul works as an assistant editor at Hindustan Times. She covers health and related topics, including ministry of health and family welfare, government of India.

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