No Evidence COVID-19 Can Increase Through Air-Con Systems

With the spread of the coronavirus pandemic, it seems that we are getting in new information every day. Much of that consists of how the virus is spread and what behaviors and activities make you more or less susceptible to contracting COVID-19. We have some idea of how the virus can be transmitted through certain surfaces like

•  Boxes and bags.
•  Clothes.
•  Countertops.
•  Other surfaces in and out of your home.

But how much do we know about how the virus spreads through the air? CDC recommends social distancing, and that a safe distance to maintain from others is at least 6 feet. More is better if you can. 

One question that we have been getting recently is in regards to spreading COVID-19 through your home or office air conditioning system. 

Can COVID-19 Spread Through Air-Con Systems?

Thankfully, there is no current evidence that supports that COVID-19 can be spread through air conditioning systems. This was recently supported by Professor Leo Yee Sin, who is the executive director of the National Center for Infectious Disease (NCID). 

A recent study by NCID researchers did find that the virus that causes COVID-19 could be found in isolation facilities, which included air ducts that were connected to the rooms of infected patients. However, the research did not support that the disease is an airborne one. The preliminary research that we have on COVID-19 as of now shows that respiratory droplets are the main transmission mechanism through which the virus is spread. 

That NCID study, which was just published in JAMA in the last few weeks, did find that patients that had been infected with the virus could cause sizable contamination to their immediate surroundings. This was specifically in regards to their isolation room before it had been cleaned. 

This study examined samples from the toilet bowl and sink of a single patient that had tested positive for the virus. Pre-cleaning, those surfaces tested positive, but after cleaning, the test samples from these areas came back negative. This was not only a way of testing for the virus on surfaces but also a way to assess if the current means of decontamination were effective. 

Though this prompted headlines around the globe that the airflow of water droplets could be a means for transmission. Professor Leo has gone on to explain the purpose of the study was to examine environmental contamination. Not how the virus is spread. 

We have seen that the virus can be transmitted via surfaces in isolation facilities. To find out if the virus can be transmitted by air and not just through respiratory droplets, this requires a different set of experiments and testing. 

Professor Kenneth Mak (director of medical services at the Ministry of Health) said the discoveries that were made in this recent NCID study were indeed in line with what we currently know about the virus being transmitted primarily through respiratory droplets. He also noted that there are some significant differences in isolation facilities’ air conditioning and ventilation systems when compared to the ones that we have at home. 

In most homes, air vents are located higher in the room, whether on the walls or in the ceiling. In isolation rooms, vents are typically located around the floor or at the bottom of a room. This can lead to respiratory droplets collecting around them via sneezing, coughing, and gravity pulling those droplets down and around those vents. 

With vents and vent systems located higher in individual rooms and not necessarily open in a way that would expose it to contamination, it would be highly unlikely that COVID-19 could spread through your air conditioning system or your home’s ventilation. 

Say you are in a home with 3 other family members, and one of your family members tests positive for the virus. With the information and research, we have access to now, self-quarantining them to a room or closed off area of your home is effective for the spread of the virus. 

With what the most recent research shows, it seems highly unlikely that this infected individual could sneeze and spread the virus through the ventilation or air conditioning system in your home. It is far more likely that another individual in your family would contract the virus by being exposed to it through:

•  Respiratory droplets.
•  Surface contact.
•  Contaminated clothing or fabric. 

As of now, we do not have supporting evidence that shows that COVID-19 can be spread through our home air conditioning and ventilation systems. With the proliferation of international news during this time, we can expect that the CDC, WHO, as well as other national, regional, and international health organizations, will be reporting any updates on the spread and transmission of the virus, if and when they discover new information.