Someone without symptoms spread the Covid-19 infection

  • What is the evidence on this?

  • What is “presymptomatic stage”?

  • How does one protect oneself from asymptomatic transmission?

  • For how long can a person spread the disease after being infected by the virus?

UPSC Can List these questions under

GS paper 2 ( Issues related to health, education and Human resources )

What is the context about?

  • Throughout the pandemic, public health officials have focused on the advice that people who have symptoms of Covid-19 should self-isolate. This is crucial, to be sure.
  • But it is also becoming “increasingly clear that there are people who are either asymptomatic or minimally symptomatic who can transmit” the virus.
  • In fact, people can start transmitting the virus 24 to 48 hours before they start showing symptoms.

What is the evidence on this?

  • It is now widely understood that around the world, the bulk of the people who get infected will not show symptoms, and will probably not even know that they have contracted the virus unless they are subjected to a serological test at some point and are found to have developed antibodies.
  • Last week, a study from China concluded that 44% of the cases who had contracted the disease had caught it from an asymptomatic person.
  • They estimated that viral shedding, which is when a person infects another, starts happening two to three days before the onset of symptoms.

 What is “presymptomatic stage”?

  • The WHO recognises three stages of COVID-19 transmission — asymptomatic, presymptomatic and symptomatic.
  • The incubation period of the virus ranges between 5-14 days.
  • “Symptomatic transmission refers to transmission from a person while they are experiencing symptoms.
  • Presymptomatic transmission is when a person spreads the disease before symptoms appear, and eventually develops symptoms themselves.
  • Asymptomatic infections are the detection of virus with no development of symptoms. Pre-symptomatic infections are the detection of virus prior to development of symptoms.

How does one protect oneself from asymptomatic transmission?

  • There is no alternative to basic safety practices such as hand-washing, wearing a mask, and social distancing. That is, till such time that a vaccine is found.

For how long can a person spread the disease after being infected by the virus?

  • The reply to this question is commonly assumed to be 14 days. However, as it is a new disease, knowledge about it is evolving.
  • In Kerala recently, a 54-year-old woman tested positive for the virus almost a month after she arrived from abroad, and had been quarantined at home ever since.
  • Recently, Telangana decided to increase the home quarantine period to 28 days, from 14 days.
  • The Union Health Ministry has advocated from the very start that patients should be followed up, at least through community surveillance, for 28 days and not 14 days.