With temperatures rising and the novel Coronavirus infection rates beginning to slow down, we’re all wondering if the COVID-19 pandemic is going to end this summer. Is it really possible that summer heat can stop COVID-19? And at what temperature does the novel Coronavirus die? Does sunlight kill the Coronavirus too, or is it just the heat, or both? Do UV rays and vitamin D produced as a result of sunlight exposure help stop the novel Coronavirus? These are all valid questions to be asking as, it turns out, there may be some truth to the COVID-19 and summer heat theory raging right now.
Does heat kill the Coronavirus?
There is a reason why the human body responds to infections by raising body temperature above normal, that is, causing fever. And that reason is that fever alone kills off a great deal of the viruses, bacteria and other infectious agents present in the body. Fever is the human body activating its immune system defenses. That’s why most people get a fever when they have a cold, the flu, a sinus infection or COVID-19, or even something more serious. Contrary to popular belief, fever should not be treated unless it causes a person to stop eating, drinking or to become lethargic, foggy-brained or bed-bound. Up to that point, fever is a protective mechanism, developed over millions of years specifically for this reason: to protect us from infectious agents and disease.
As both scientific studies and empirical evidence prove, fever is meant to target infectious agents in the body, viruses included. Some viruses have developed protective mechanisms to elude the immune system so it doesn’t bring down fever on them because that would destroy them, or at least vastly reduce their numbers. Others, while susceptible to heat, are more resilient and require higher temperatures to render them non-infectious. For example, a common cold Coronavirus can be pretty much reduced to nothing by running a fever for a few days, and further immune system intervention of course. But SARS-CoV-2, the Coronavirus causing COVID-19, is resistant to a lot higher temperatures – higher than the human body could reach physiologically and far higher than it would be safe for us to experience. Fortunately, surfaces, objects and plenty of materials can reach high enough temperatures to kill the SARS-CoV-2 Coronavirus, if they can’t be disinfected that is. But at what temperature does the novel Coronavirus die?
At what temperature does the Coronavirus die?
According to a study done on the SARS-CoV Coronavirus, heat treatment of the virus at a temperature of 56 degrees Celsius for 30 minutes reduced viral load to undetectable levels which pretty much means the virus died off. Incubation of the virus at 60 degrees Celsius killed off the virus completely. While no tests have been done on SARS-CoV-2 specifically, it is likely the novel Coronavirus is similar in this respect to the 2002-2004 SARS-CoV Coronavirus.
That would mean that the temperature at which SARS-CoV-2 will die is in the 56-60 degrees Celsius (132.8-140 degrees Fahrenheit) range. To be on the safer side, consider the 60 degrees Celsius/140 degrees Fahrenheit temperature point. But the contaminated surface, material or object would need to maintain that temperature for 30 minutes. This is a temperature that the human body simply cannot reach naturally, and even if it could somehow reach it, it would be incompatible with life. But not necessarily a problem for clothes washed in the washing machine and surfaces or objects in direct sunlight during hot summer days.
Does summer heat stop Coronavirus?
The novel Coronavirus, like all other viruses, is impaired or completely inactivated by heat. According to extrapolated data, a temperature of 56 degrees Celsius (132.8 degrees Fahrenheit) maintained for 30 minutes reduces SARS-CoV-2 load to undetectable levels, while a temperature of 60 degrees Celsius (140 degrees Fahrenheit) maintained for 30 minutes kills the virus. But ‘summer heat’ is a fairly general term that can include temperatures ranging from roughly 25 to 42 degrees Celsius (77-107.6 degrees Fahrenheit). So what exactly about ‘summer heat’ could stop the Coronavirus, if anything? Here are some aspects to consider:
- Surfaces exposed to direct sunlight in summer reach high temperatures – the longer the exposure, the higher the temperature. For example, you can fry an egg on a car windshield, car roof, on the pavement or middle of the road during a hot summer day. It stands to reason that such high temperatures would have a disinfecting effect and possibly also reduce virus numbers or kill the Coronavirus off from a surface.
- Not all surfaces reach high enough temperatures in summer to stop the Coronavirus. For example, surfaces from indoor settings where there is air conditioning or a fan, objects in the shade or simply areas where temperatures don’t rise very much during summer. The lower temperatures in indoor settings may even help viruses like the novel Coronavirus thrive.
- The choice of lifestyle can stop or further COVID-19 numbers. Some people are always outside in the sun in the summer and, unintentionally or not, practice social distancing by doing a lot of activities alone or in small groups, choosing to ride a bike to work instead of the bus or metro or taking their own car etc. Others spend a lot of time indoors (where the virus can thrive even in summer due to air conditioning lowering the temperature, for example) or prefer groups and group activities, increasing their chances of infection.
- Other factors such as region, climate, humidity further impact virus viability, rendering render the term ‘summer heat’ simply too general. For example, in humid climates, humidity contributes to viruses viability.
- The more people touch a surface or object, the higher the chances of contamination. Crowded places such as public transportation and public surfaces such as door knobs or handles, handrails etc. require disinfecting or hand washing after touching. There little summer heat can do with surfaces and objects that come into contact with lots of people throughout the day.
- Not all materials reach the same temperatures. Metal can get extremely hot in direct sunlight in the summer, but can stay really cold indoors. Some clothes can be washed at 90 or 95 degrees Celsius, while others can only be washed in cold or lukewarm water. The only solution is to disinfect anything you feel may potentially be contaminated.
Does UV light from sunlight kill the Coronavirus?
UV stands for ultraviolet and refers to ultraviolet radiation from sunlight. In addition to heating, stimulating melanin production in the skin and triggering the tanning process, stimulating production of vitamin D, destroying collagen in the skin and inducing early skin aging, ultraviolet radiation also has a germicidal effect, meaning it’s disinfecting. But while ultraviolet radiation from sunlight inactivates viruses, bacteria and other pathogenic microorganisms, exerting a disinfecting effect, it doesn’t work as effectively as UV germicidal lamps that are used for disinfecting surfaces. What this means is that plain sunlight likely won’t kill the Coronavirus from surfaces, despite it being disinfecting in nature. A surface heating to extreme temperatures for a certain amount of time as a result of exposure to sunlight might though.
Does vitamin D help with Coronavirus?
In addition to heat and UV light, sunlight is also a trigger for vitamin D production in the skin. Research has revealed that vitamin D has protective immunological effects which means adequate levels of vitamin D could potentially hold benefits for the prevention and symptoms management of COVID-19 (read more about vitamin D and Coronavirus). Unfortunately, sufficient vitamin D can only be procured from sunlight exposure and supplementation with either synthetic vitamin D or natural supplements such as cod liver oil or other fish liver oils. Regular foods that are marked as sources of vitamin D contain only small amounts of the essential nutrient and are not enough to prevent a deficiency.
If anything, summer time can up our vitamin D production for a stronger, smarter and better regulated immune system which is one of the best allies against COVID-19, especially considering there is no real treatment for the infection. If heat and UV light cannot be relied on for disinfecting surfaces contaminated with the novel Coronavirus, at least vitamin D can help slow down infection rates and potentially contribute to better outcomes.
The novel Coronavirus is a source of worry and anxiety both because of its high infectiousness and because of its potential for serious outcomes, moreso than the Coronaviruses that cause the common cold. Which explains why everyone is brain storming for solutions, including considering summertime and summer heat for stopping or at least slowing down the spread of the novel Coronavirus. Unfortunately, despite the benefits of summertime and summer heat and sunlight for health, their anti-COVID effects are fairly limited. The novel Coronavirus is stronger and smarter than common cold Coronaviruses, and more infectious. However, practicing good hygiene, social distancing and getting in the sun for that vitamin D can potentially help slow down COVID-19, if not stop it.