How Long Does COVID-19 Last on Surfaces? Understanding Surface Contamination

The COVID-19 pandemic has changed our lives in countless ways, and understanding how the virus spreads is key to protecting ourselves and our loved ones. While we often hear about person-to-person transmission through respiratory droplets, another important route to consider is surface contamination. Have you ever wondered how long the SARS-CoV-2 virus, the one that causes COVID-19, can actually survive on the everyday objects we touch? This is a vital question, especially when you're out and about, handling groceries, or even just using public transport. Let's dive into what scientific studies tell us about the persistence of the coronavirus on various surfaces, helping you make more informed decisions about hygiene.

Understanding Viral Persistence on Surfaces

The virus that causes COVID-19, SARS-CoV-2, is primarily known to spread through respiratory droplets when an infected person coughs, sneezes, or talks. However, it's also possible to contract the virus by touching a contaminated surface and then touching your eyes, nose, or mouth. While this is not considered the main transmission route, it's a significant one that we can actively manage. The key question is: how long can this virus remain infectious on different materials?

Scientific research has been actively investigating this very question. Two notable studies, published in the New England Journal of Medicine (NEJM) and The Lancet, have provided valuable insights into the survival times of SARS-CoV-2 on various surfaces. It's important to remember that while these studies can detect the virus, the actual infectivity can be influenced by environmental factors like temperature and humidity. Think of it like this: finding a tiny seed doesn't automatically mean it will grow into a plant; conditions need to be right. Similarly, the virus might be present, but its ability to infect can vary.

How Long Does Coronavirus Survive on Common Materials?

Let's break down the findings for different types of surfaces:

Plastic Surfaces

Many everyday items are made of plastic, from remote controls and phone screens to grocery carts and medical equipment. Studies have shown that SARS-CoV-2 can persist on plastic surfaces for a notable duration. While the NEJM study detected infectious virus on plastic for up to 3 days, The Lancet study found it could be detected for even longer, up to 7 days. This means that frequently touched plastic surfaces require diligent cleaning and disinfection.

Stainless Steel

Stainless steel is another common material found in kitchens, hospitals, and public spaces. Similar to plastic, it can harbour the virus for a significant period. The NEJM study found no viable virus after 3 days on stainless steel. However, The Lancet study reported detecting viable virus for up to 7 days. This highlights the importance of regularly cleaning high-touch stainless steel items like doorknobs, railings, and countertops.

Copper

Copper is less common for large surfaces but is used in some fixtures and decorative items. It appears to be less hospitable to the virus. Researchers found that SARS-CoV-2 was less stable on copper, with no viable virus detected after just 4 hours. This suggests that copper might be a more resistant material compared to plastic or stainless steel.

Cardboard and Paper Products

We encounter cardboard and paper daily, from food packaging and shipping boxes to tissues and currency. Studies indicate that the virus doesn't survive as long on these porous materials. The Lancet study found no viable virus on printing paper or tissue paper after 3 hours. However, it's interesting to note that the virus could be detected on paper money for up to 4 days. This is a good reminder to handle cash with care and wash your hands afterward.

Glass

Glass surfaces, such as those on windows, mirrors, and phone screens, showed a moderate survival time for the virus. The Lancet study reported that no viable virus could be detected on glass surfaces after 4 days. While not as long as plastic or stainless steel, it still necessitates regular cleaning, especially for frequently touched glass items.

Wood

Wood is a common material for furniture, tabletops, and shelving. While specific studies on wood survival times for SARS-CoV-2 are less detailed in the primary research, it's generally understood that porous materials like wood may not sustain the virus as long as non-porous surfaces like plastic or metal. However, it's always best practice to clean wooden surfaces that are frequently touched.

Factors Influencing Viral Survival

Several factors can influence how long the coronavirus remains viable on surfaces:

• Temperature: Higher temperatures tend to reduce the survival time of viruses.
• Humidity: Similar to temperature, humidity levels can also affect viral stability, with higher humidity sometimes leading to shorter survival times.
• Surface Type: As we've seen, porous vs. non-porous surfaces play a significant role.
• Amount of Virus: The initial viral load on the surface can influence how long it remains detectable.

Imagine you're at the supermarket. You pick up a plastic-wrapped item, place it in your cart, touch the cart handle, and then perhaps touch your phone. If someone with COVID-19 recently touched that same cart handle or item, there's a possibility the virus could be transferred. Knowing that plastic and metal can harbour the virus for several days underscores the importance of hand hygiene after such exposures.

What About Food, Water, and Clothing?

Food: The Centers for Disease Control and Prevention (CDC) notes that coronaviruses, as a group, generally do not survive well in food or water. The primary risk of transmission is through respiratory droplets, not through consuming contaminated food or water. However, practicing good food hygiene, like washing hands before preparing or eating food, is always recommended.

Clothing and Shoes: While it's generally not necessary to launder clothes after every outing, it's a good idea to wash them if you've been in close contact with others or if someone coughed or sneezed near you. The virus doesn't typically survive for extended periods on fabrics compared to hard surfaces. Similarly, while shoes can track in germs, the risk of transmission from shoe soles is considered low, but cleaning them occasionally is not a bad idea.

Practical Steps for Surface Hygiene

Given this information, what practical steps can you take? It's all about consistent, mindful cleaning:

1. Clean and Disinfect Frequently Touched Surfaces: Focus on items like doorknobs, light switches, remote controls, countertops, phones, keyboards, and faucet handles. Use household disinfectants according to product instructions.
2. Wash Your Hands Regularly: This is your first line of defense. Wash your hands with soap and water for at least 20 seconds, especially after being in public places or touching surfaces that others may have touched.
3. Use Hand Sanitizer: When soap and water aren't available, use an alcohol-based hand sanitizer with at least 60% alcohol.
4. Be Mindful of Groceries and Packages: While the risk from packages is low, wiping down high-touch surfaces of groceries (like plastic packaging) and washing your hands afterward is a sensible precaution.
5. Avoid Touching Your Face: Try not to touch your eyes, nose, and mouth with unwashed hands.

When to Be Extra Cautious

You might want to be extra diligent with cleaning and hygiene in the following situations:

• If someone in your household has tested positive for COVID-19.
• If you have recently returned from a high-risk area.
• If you have a compromised immune system or are at higher risk for severe illness.

Understanding how long the coronavirus can survive on surfaces empowers you to take targeted actions. By combining surface cleaning with diligent hand hygiene, you significantly reduce your risk of contracting and spreading COVID-19. Stay informed, stay safe!

Frequently Asked Questions (FAQ)

Q1: Can I get COVID-19 from touching a surface?

A1: Yes, it is possible, although it's not the primary way the virus spreads. If you touch a surface contaminated with SARS-CoV-2 and then touch your eyes, nose, or mouth, you can become infected.

Q2: How often should I clean my phone?

A2: Given that phones are frequently touched and made of plastic or glass, it's a good idea to clean and disinfect your phone daily, especially if you use it in public places.

Q3: Do disinfectants kill the coronavirus on surfaces?

A3: Yes, most common household disinfectants are effective against SARS-CoV-2 when used according to the manufacturer's instructions. Look for disinfectants that are registered with your local health authority for use against the virus.