Coronavirus: WHO retracts statement within a day that said asymptomatic COVID-19 carriers cannot spread infection. Here is an explainer

The world continues to see a spike in the number of deadly coronavirus infection cases. India is one of the worst affected countries in the world, even as experts worry we might not have witnessed the peak of the infection yet and a big percentage of those who constitute the illness in India are asymptomatic.

This is rather worrying, considering World Health Organisation let out a statement recently, saying that COVID-19 transmission rate from asymptomatic patients is "rare". However, soon after, they retracted the statement, adding that the statement was misinterpreted and much data remains unknown and there, actually was a 40% chance of patients transmitting the illness onto others without being symptomatic. The debate created a big furore and sparked controversy in the community.

In several states, including in India, there is a lot of testing protocol around the same. While WHO's statement had led to a lot of confusion, asymptomatic cases seem to constitute a bulk load of global cases and are scary.

Asymptomatic coronavirus still remains to be a hot topic and invites a lot of confusion. We give you an explainer about the same

There is no one set meaning of the term 'asymptomatic'. Some patients affected by the novel coronavirus may be infected but not document any of the typical symptoms, including coughing, fever or breathing issues. These are what experts term 'asymptomatic or atypical coronavirus positive' cases. Since they do not show or feel any of the symptoms per se, they can go to spread the infection without knowing themselves.

In some cases, what further creates an alarming situation is that the symptoms turn up in a mild way, which are usually unheard of and left untreated. Or, the symptoms only turn up much later, aggravating the spread of the disease. Since they spread the disease without knowing, asymptomatic patients are called "silent spreaders" of the disease. While it existed from the start of the infection, the most prevalent case was when half of the infected people onboard the Japanese cruise were found to be asymptomatic.

Transmission, with any viral infection, increases when the viral load in the body steadily goes up.

Rates of asymptomatic transmission have seen a varying trend ever since the pandemic started to spread rapidly and it still remains to be studied how big of a "threat" asymptomatic transmission in COVID-19 is.

While symptomatic patients transmit the infection through direct transmission modes like coughing or sneezing, in those with unknown, or undetected symptoms, the disease could potentially even spread through modes like talking loudly, shouting or simply mingling around in a crowd.

People, with or without symptoms can readily spread COVID-19 as newer studies suggest that people may be the most infectious before they start experiencing typical symptoms.

That being said, experts say that out of the two, symptomatic coronavirus cases tend to be more contagious than asymptomatic ones. Those with trivial symptoms remain contagious for a longer time than those who have atypical symptoms. If you're asymptomatic—i.e. not sneezing or coughing—then you're not releasing as many droplets, and thus, potentially not spreading as much of the virus and not leaving the virus environment to breed. Research conducted at the Department of Infectious Diseases at Zhongnan Hospital, in Wuhan, China found the same in a pool of COVID-19 patients. It was observed that the asymptomatic carriers were contagious for 3-12 days at maximum, while those who did have the typical symptoms could possibly spread the virus for 16-24 days, implying that those with symptoms can spread the virus for three times longer than those who are asymptomatic.

Rigid contact tracing and widescale testing is the only way to prevent or stop the spread of coronavirus. That being said, some states have different viewpoints regarding testing and infection treatment. In many places, since asymptomatic COVID-19 doesn't show typical symptoms or require hospitalisation, home quarantine and isolation is suggested to break the chain of transmission.

Apart from that the prevalent measures such as wearing a mask, social distancing, aka, non-pharmaceutical measures can help contain the spread until we have a proper vaccine or treatment in sight available, which will take a while.

There is no real way of preventing coronavirus altogether. However, if you suspect a case of asymptomatic coronavirus, or have been exposed to someone found COVID-19, self-quarantine and isolation for a minimum of 14 days (which is like the peak time for the virus to incubate and spread once it enters the body) is vital. You may feel fine and not experience symptoms, but it's important to know that you can silently spread on the symptoms to others.

When it comes to recovery, some bodies of research have also found that asymptomatic coronavirus patients gain antibodies the same way, as those with typical symptoms post the infection. However, conclusive evidence is still needed to confirm the same.