According to a study by Retired US Army Virologist Jose-Luis Sagripanti and David Lytle, a former US Government virologist and published in the journal Photochemistry and Photobiology, sunlight could kill the coronavirus in 30 minutes. Powerful ultraviolet or UV light was found to be able to destroy 90% of the coronavirus that had just been coughed or sneezed onto a surface in just half an hour, by virologists. Other studies have even claimed that the sun could also wipe out parts of the virus which lingered in the air, completely in just 6 minutes.
How can the sun kill the virus?
The coronavirus SARS-CoV-2 that causes COVID-19 is protected by an external casing which is degradable under heat. This heat can also be generated from the warmth of the body of the person it infects. When the virus is coughed or sneezed into the air or onto a surface the UV light from the sun can effectively destroy this coating. The virus will then be exposed and will soon dry out and decay in the sun.
Vitamin D which is produced in your body when your body is exposed to sunlight can help in boosting immunity to fight off the virus. Now, some researchers are suggesting that outdoors may be safer than being cooped up inside. This is because of the belief that COVID-19 can still survive indoors where the UV light cannot get to them and therefore stay infectious for days.
The UV rays in sunlight can destroy aerosols carrying the coronavirus
Professor Keith Neal, an epidemiologist at the University of Nottingham went explains “Sunlight includes UV radiation. This damages DNA and RNA. Viruses left on surfaces outside will dry out and be damaged by UV light in sunlight. Talking and coughing can produce droplets and aerosols. Droplets, which are larger than aerosols, carry more virus but fall rapidly to the ground under gravity. Aerosols are smaller and can drift further but also dry out quickly because they lost water content”.
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The summer months can possibly decrease the number of cases but Fears of a second wave are expected in winter
While this study sparks hope of a possible way to get rid of the dreadful disease it also adds to the fears of a second wave of COVID-19 in the winter months. It has been feared that when lockdown restrictions are eased and the hours of daylight become shorter in the winter, the virus might return. Moreover, the winter is the time when v0iral illnesses in general become quite common.
Unfortunately, it is during the winter months being December to March, that the virus will be infectious. In colder climates, it can live on surfaces for up to a day or more “with risk of re-aerosolization and transmission in most of these cities.
How can the virus be killed by sunlight in the fall and winter season?
As per a report in the UK Telegraph researchers estimated that it would take around 34 minutes in summer for the virus to be completely destroyed. But, in the autumn season, it would take at least an hour and 40 minutes while in winter it would take up to 4 hours in the spring and more than 5 hours in the winter.
Making people stay indoors could possibly increase the spread of the virus
Researchers have said: “Forcing people to remain indoors may have increased or assured contagion of Covid-19 among same household dwellers and among patients and personnel inside the same hospital or geriatric facilities. In contrast, healthy people outdoors receiving sunlight could have been exposed to a lower viral dose with more chances for mounting an efficient immune response”
“The viral persistence estimated here for cities at northern latitudes where Covid-19 expanded rapidly during winter 2019-2020 and relatively higher viral inactivation in more southern latitudes receiving high solar radiation during the same period, suggests an environmental role for sunlight in the Covid-19 pandemic”.
Sunshine is effective in destroying the coronavirus
The study by Dr. Jose-Luis Sagripanti, and Dr. David Lytle, stated that the peak summer sunshine in London in June proved to be effective in reducing the infectivity of the coronavirus by 90%.In comparison to this duration it would take 1 hour and 17 minutes to destroy the virus in the capital in September and a whole 3 hours in March.
However, during the winter the virus could thrive for more than 5 hours due to weak sunlight and can potentially stay alive for days indoors. In countries which have longer winters the sunlight is even less powerful which is why it would take slightly longer for the virus to be destroyed by the sunlight in these countries.
Many studies have highlighted similar findings
In May, a University of Oxford study revealed that the overall global coronavirus death rate was 0.2%, surprisingly in the colder northern hemisphere was 0.3%. In Italy, the researchers observed that the warmer south was less affected by the coronavirus in comparison to the north. In fact, several studies even suggest that vitamin D which is primarily obtained from the sun can help in preventing people from getting severely infected with COVID-19. Moreover, research has also established a link between COVID19 fatalities and vitamin D deficiency.
Is it proven that the sun can kill the virus?
It is a proven fact that UV light has a sterilizing effect as its radiation damages the genetic material of viruses potentially destroying their ability to replicate. Almost all viruses including SARS-CoV-2 are covered with a thin membrane which can easily be broken apart by sunlight.
A study published in Scientific Reports by a Columbian University 2 years ago showed that light is capable of killing more than 95% of pathogens like the coronavirus. The findings of one study by the US National Biodefense Analysis and Countermeasures Center also showed that the coronavirus coughed into the air can be killed by strong sunlight in 6 minutes. However, the deadly virus is still present even in countries with extremely hot weather like the Middle-East and West Africa.
To remain safe
But before heading outdoors and celebrating, one should realize several studies have proved that the spread of the virus does not slow down in warmer weather. Additionally, statistics show that new infections are at a record high in some of the hottest climates in the country. In tropical climates like Pakistan and India, the virus has seen sudden unprecedented hikes in the number of infected cases although unlike European countries, fatalities are low.
Don’t just count on sunlight to save you. It is still better to stay at home and avoid those that could infect you with the virus. Follow the experts advice, practice social distancing, wash your hands and wear a mask when venturing out.
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