Updated: May 7
What is SARS-CoV-2?
SARS-CoV-2 is the virus which causes COVID-19, a disease which started in Wuhan, China in December 2019. Since then it has spread to more than 210 countries, the number of cases outside of China being much higher than China itself.
Coronavirus is a family of viruses known to cause Upper respiratory symptoms and generally not severe. There have been previous outbreaks of Coronavirus, in 2002 of SARS (Sudden Acute Respiratory Syndrome) in China and in 2012 of MERS (Middle east respiratory syndrome) in the Middle East. Both are severe illnesses which were contained.
SARS-CoV-2 is the name given to the new coronavirus that started causing illness varying from mild flu like illness to severe respiratory distress, when a person is unable to breathe, and lungs are unable to maintain oxygenation to the body. It affects the upper respiratory tract, lungs, gut, heart and rarely the eyes.
How is SARS-CoV-2 different?
Even though it causes flu like illness, this is different. It has high viral load and is transmissible before and during infection, and possibly for some time after recovery. The disease spectrum is from mild illness to fatality – more than the Flu virus.
What are the symptoms?
80% of the cases are mild and will recover spontaneously. 20% have lung complications.
The most common symptoms are-
myalgia or weakness
loss of taste and smell.
diarrhoea (less common)
Some patients will develop pneumonia and lung complications, leading to lack of oxygen in the body. The death rate is high in people who develop these symptoms.
Shortness of breath
Chest pain or tightness
Bluish lips and extremities
Please contact a health provider if this happens.
How fatal is the disease?
It can be fatal, with case fatality rates from 0.2- 7.7%. The wide range depends on population demographics, being higher specially in countries where percentage of older population is high.
Those above 60 years of age made up just 19% of coronavirus cases but accounted for 63% of the fatalities. Those who are 40 to 60 years old accounted for 30% of the fatalities, while only 7% of the fatalities were in those younger than 40.
As many as 86% of the fatalities had conditions such as diabetes, hypertension, heart and kidney disease. Mortality rates start increasing rapidly from age 60, highest being 14.8% in people aged 80 and above and is higher if a person has chronic diseases like diabetes, obesity, heart disease, hypertension etc. Among infected cases ratio of males to female is high, 76% males and 24% females. Men also account of 73% deaths.
Are there tests available?
RT PCR is a test available which is specific for coronavirus. It uses a specimen taken as a swab from throat/nose/bronchial washings and reports positive early in the course of illness and can report positive up to 2 weeks after recovery. This test typically takes 1-2 days for reporting. However, it misses positive cases in up to 10-30% cases depending on the site where it has been taken.
There is also a serological test which tests for protective immunity. It is used for many viral infections already. It tests for protective immunity and is not good for detecting acute infections. It becomes positive from day seven for IgM (immediate immune response) and day fourteen for IgG (delayed immune response). It has a vital role not only in checking who has developed immunity in the community but also to make policy decisions on how to manage the disease at a population level.
How does SAR-CoV-2 spread?
Aerosol/droplet spread: When a person sneezes or coughs the droplets carrying the virus can spread to a distance of 6 feet or more.
Fomites: If a virus settles on a surface or reaches there by direct contact from an infected person it can become a source of infection if a person touches their face after touching the infected surface. Coronavirus survives on various surfaces for varying time. This is a list of survival time on various surfaces, giving us insights to what materials to avoid, and how aggressive we should be to sanitize.
- Steel: 4 days
- Cardboard: 24 hours
- Copper: 4 hours
- Plastics: 4 days (another reason to avoid plastic bags).
Airborne spread is also being considered – a person spreading the virus by speaking loudly – but the evidence is inconclusive so far.
Faecal spread is also being considered but results are inconclusive at present.
What treatments are available?
As it is a new disease, we do not have any definitive treatment or vaccine for it, though there is extensive research going on world-wide. Some drugs like hydroxychloroquine, Azithromycin, Redesmivir, convalescent plasma are being tried and we hope to have results from various trials around the world in near future.