In light of the quickly spreading novel coronavirus, you’ve probably heard the advice to avoid crowded places, wash your hands often and disinfect shared spaces if you think you’re sick. But why are those precautions so important?
COVID-19, the disease caused by the novel coronavirus, is transmitted through droplets. If someone with the disease coughs or exhales, anyone who touches the surface where those droplets land and then touches their eyes, nose or mouth could get sick, according to the World Health Organization (WHO).
People can also catch the disease if they breathe in droplets from someone who is infected, so the WHO recommends staying more than one metre away from someone who is sick.
The organization says studies suggest the novel coronavirus is primarily transmitted through contact with respiratory droplets, as opposed to through the air.
How long can COVID-19 live on surfaces?
An analysis published in March in the Journal of Hospital Infection looked at 22 studies about coronaviruses and surfaces. It found that human coronaviruses can survive on surfaces like metal, glass or plastic for up to nine days. Agents with about 60 per cent alcohol are effective disinfectants to clean them.
Another study, by the U.S. government and other scientists, found that the virus that causes COVID-19 — after being sprayed into the air — could be detected up to three hours in the air, four hours on copper, up to 24 hours on cardboard and two to three days on stainless steel. (Those findings have not been peer-reviewed.)
The longevity of the coronavirus depends on a number of factors, including the type of surface, as well as the humidity or temperature of the environment.
The WHO suggests cleaning a suspected infected surface with a simple disinfectant, and then cleaning your hands with an alcohol-based hand wash or soap and water.
How long can people be infected with the virus for?
After being exposed to the novel coronavirus, the average time to develop COVID-19 symptoms is about five days, according to Dr. Eleanor Fish, a professor in the department of immunology at the University of Toronto and a scientist at the University Health Network.
While five days is the average, it can be anywhere from two to 14 days. The vast majority of people — 97 per cent — show symptoms of COVID-19 within eleven-and-a-half days, Dr. Fish said.
However, there are some rare cases where people who have COVID-19 don’t show any symptoms, or don’t show the ones commonly associated with the disease, such as coughing, shortness of breath or fever.
The risk of catching COVID-19 from someone with no symptoms is low, according to the WHO, but the organization also says since many people with the disease only feel mild symptoms, it is still possible to catch it from someone with symptoms similar to a common cold.
If someone has COVID-19, the length of their sickness will depend on how many particles they were infected with, whether they have any additional health conditions and their general health level, Dr. Fish said.
“If you’re a healthy individual and you have a robust immune response, then the likelihood, apparently, is that you will have a mild disease and you can self-quarantine and recover fairly quickly,” she said.
People who have an autoimmune disease, hypertension or any pulmonary issues such as chronic bronchitis or asthma, are more at risk of having a more severe and long-lasting bout of COVID-19.
“It’s not just the amount of virus but it’s the response to those infections, which is a big inflammation in the lungs that might take longer to resolve in different individuals,” Dr. Fish said. “Some people recover within a week or so and some may take considerably longer.”
Elderly people are also more at risk because their immune systems tend to be less robust, Dr. Fish said.
How to protect yourself
Dr. Fish said because there are no community clusters of the virus in Canada right now, it’s important for people to take a responsible attitude. If someone thinks they have the virus, they should self-quarantine and contact their doctor or local public health authority.
“If any individual is suspicious about their health, it is incumbent upon that individual not to be in contact with others.”
The WHO recommends washing your hands regularly, avoiding touching your eyes, nose or mouth, covering your mouth and nose if you sneeze or cough and staying home if you feel unwell.