Breathing or drooling onto a pillow during sleep can transfer viruses onto the pillow. The virus may not only stay on the pillow cover but can also enter the pillow stuffing, becoming a potential source of virus transmission.
Understanding the different routes of virus transmission has become critical during the COVID-19 pandemic. The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and other such viruses that affect the respiratory system, generally spread by coughing, sneezing, or by saliva coming out of the mouth when talking.
The virus travels in the air via the droplets expelled from an infected person’s nose or mouth. Hence, there are guidelines for social distancing during this pandemic.
Apart from such direct transmission, the droplets with the virus may land on surfaces, such as counters, tabletops, or other frequently touched surfaces. Coming in contact with contaminated surfaces is also another route of virus transmission.
Usually, any surfaces frequently touched by people are disinfected regularly. This is especially critical in public places that are used by many people.
With travel curbs easing in many parts of the world, sharing of items used during traveling could become a potential source of virus transmission, even after disinfecting the items.
Virus transmission by microfiber pillows
One commonly used item that is usually shared, especially during travel, is a pillow. Today’s pillows are made of stuffing covered with fabric. The stuffing in about half the pillows used today in the US and China is microfibers.
A new study by researchers at the Department of Environmental Science and Engineering, Xi'an Jiaotong University, China, and published in the journal Ecotoxicology and Environmental Safety suggests that respiratory pathogens can not only fall on the fabric covers but can also penetrate the outer cover and go into the microfiber stuffing. The SARS-CoV-2 virus can remain alive on fibers for several hours to several days under room temperature. Once the particles enter the microfiber stuffing, it is very difficult to disinfect the pillows using standard sanitizing methods.
Whether virus particles penetrate the fabric covers depends on the size of the particle and how densely the fabric is weaved. One study reported that cotton fabrics with 80 threads per inch allowed 86% of NaCl aerosols 0.3–1 µm large, and polyester fibers allowed about 76% of the particles.
Using common pillows while traveling is risky
Although current practices for disinfecting aircraft, trains, buses, and hotels include cleaning surfaces, towels, and other items, there is not much being done for sanitizing pillows.
In another study, researchers investigated the hotel rooms of two patients with COVID-19 before the onset of symptoms. They found the pillows had a significant amount of the virus in just 24 hours.
Furthermore, guidelines for screening travelers differ across the world, and it is challenging to identify asymptomatic travelers. When such travelers shed virus on pillows, which can potentially penetrate the outer covers, reusing these pillows becomes risky and could cause transmission of the virus.
The risk is higher is trains where bedding is not changed en route, say the authors, for example, in couchette trains in China. So, if a traveler boards the train at intermediate stops, they may be exposed to used items, increasing their risk of being exposed to the virus.
The risk may be slightly lower in airplane travel as there are no intermediate stops, and all the passengers and crew travel from one point to the final destination.
Current CDC guidelines do recommend that if a symptomatic traveler is identified during or immediately after a flight, items that cannot be cleaned should be appropriately disposed of. However, this does not protect against asymptomatic passengers who may have shed virus.
Mitigating the risk
No studies to date have investigated whether the SARS-CoV-2 virus is present in pillow stuffing and how long it could survive. The risk of transmission of the virus via pillows is also unknown.
So, the best strategy, until the risk is known, is not to reuse pillows and dispose of them after a single-use. However, this will create additional problems of waste and pollution.
The authors recommend another strategy. The pillow could be sealed in a reusable plastic bag, like a Ziploc bag, which will prevent any particles from getting into the stuffing. A fabric cover could be used on top of the plastic.
After use, the plastic wrap could be removed, and a new cover could be used. The used plastic can be disinfected in hot water at 50–70 °C without any loss in integrity.
Travelers could also bring their own pillows rather than using the pillows provided, thus reducing the risk of virus transmission.