A study just blew up everything we thought about sunlight and COVID-19

When positive COVID-19 cases began spiking in July, experts were forced to revisit the solar ultraviolet radiation theory–which Ladders covered in greater detail here.

Some elements of this projection have remained consistent in the months since the preliminary analysis was published, like SARS-CoV-2 being less stable in warm temperatures, for instance. But others have been repudiated by leading virologists.

A new paper from the Geographical Analysis journal presents a sobering contrary interpretation of the available data.

“The novel SARS‐CoV2 has disrupted health systems and the economy, and public health interventions to slow its spread have been costly. How and when to ease restrictions to movement hinges in part on whether SARS‐CoV2 will display seasonality due to variations in temperature, humidity, and hours of sunshine,” the researchers write in the report’s abstract.  The results support the hypothesis that incidence of the disease is lower at higher temperatures and higher levels of humidity. Sunshine, in contrast, displays a positive association with incidence of the disease.”

The findings, helmed by Antonio Páez, a professor and researcher at McMaster’s School of Geography & Earth Sciences, locate a simple explanation for sunlight’s positive and negative influence on COVID-19 cases numbers.

After analyzing provinces in Spain that were disproportionately impacted by the novel coronavirus, Dr. Páez and his team calculated a 3% decrease in COVID-19 cases for every percentage increase in warmth and humidity. That explains the negative correlation: sunlight, just as it was previously determined, destabilizes coronaviruses.

The positive spike in cases under the same circumstances, however, was linked to a pervasive failure to adhere to social distancing mandates while enjoying summer festivities.

“There is a lot of pressure to reopen the economy, and many people want to know if it will be safer to do so in the summer months,” Dr. Páez, explained in a media release. “Restrictions in movement, which have begun to ease around the world, hinge in part on how SARS-CoV2 will be affected by a change in season.”

This also explains why younger demographics are propagating the spread of the virus.

Cluster spreading has been identified by multiple health systems as the most formidable contributor to outbreaks in the US.

Older populations are less likely to evidence necessary t-cell memory important to auto-immune functions, compared to younger populations.

Because of this, the young are less likely to exhibit characteristic symptoms of COVID-19 before viral clearance (many don’t get sick at all).

Without physical indicators of illness, these continue to interact with vulnerable communities with fewer biodefenses to propel herd immunity.

After Spain officially declared a state of emergency, longer hours in the sun yielded a patterned correlation with positive COVID-19 cases.

“We will likely see a decrease in the incidence of COVID-19 as the weather warms up, which is an argument for relaxing social distancing to take advantage of the lower incidence associated with higher temperatures,” he says. “But a more conservative approach would be to use the months of summer to continue to follow strict orders to remain in place and to crush this pandemic.”

Although understandable, quarantine angst appears to induce a nationwide disparate response.

In a recent forum presented jointly by the Harvard T.H. Chan School of Public Health and the New England Journal of Medicine,  Dr. Anthony Fauci likened our fight to contain the coronavirus to Crew.

All members have to row in unison if we’re going to progress at a meaningful place. Otherwise, we’ll be at this plateau indefinitely.

“Wearing a mask is definitely one of them, as is physical distancing, as is avoiding crowds, as is closing bars, as is washing your hands,” Fauci explained. “I’m pleading with people to consider doing this consistently because, you’re right, if half of the people don’t do it, it kind of negates the overall purpose.”