You can’t run from the potentially deadly SARS-CoV-2 virus, but you might be able to hide in the forest, according to some research coming out of China.
In one of the stranger studies of the now 18,112 pandemic-linked investigatoins published on the MedRxiv website, researchers from the University of Hong Kong looked at infections in counties across the U.S. and concluded that “green spaces, especially forest, (are) linked to lower SARS-CoV-2 infection rates.”
This should come as especially good news to Alaskans living in a state where green space abounds. It might also help explain in part the state’s low death rate from COVID-19, the disease that has killed nearly 612,000 of the almost 36 million U.S. citizens known to have been infected with SARS-CoV-2, according to the latest data from the World Health Organization.
The Alaska death rate of 53.4 per 100,000 since the pandemic began in the spring of 2020 is the third-lowest in the nation, according to the Worldometer tracker. Only Hawaii and Vermont are reported to have lower death rates.
All are states with a lot of readily accessible green space as is Maine, which is fourth-lowest in the nation with a death rate of 67 per 100,000, according to Worldometer.
For comparison sake, the rate in New Jersey – where deaths have been concentrated in the urban areas surrounding New York City (NYC) – has now hit 300 per 100,000. More than half of those deaths have taken place in the half-dozen heavily developed counties nearest the Big Apple.
The city itself has led New York state to a position of the second deadliest state in the nation with a tally of 279.3 of every 100,000 residents dead from COVID-19.
That is more than five times the death rate in Alaska, where COVID-19 has claimed the lives of 391 people. The pandemic has for reasons unclear largely spared the 49th state.
Last Frontier hideout
The state’s overall case fatality rate (CFR) – the number of people who are known to have had COVID-19 and died – is around 0.5 percent. Nationally, Worldometer puts the U.S. rate at 2 percent.
In New Mexico, which reports an infection rate almost identical to that of Alaska (10,258 infections per 100,000 residents versus 10,260 infections per 100,000 residents), the death rate is near four times higher than in Alaska.
Why Alaska has fared so much better than other states is a phenomenon yet unexplained. The state’s 17-month death count of 391 COVID-19 victims is lower than the state’s accident death count of 439 for the 12 months of 2017, the last year for which the Centers for Disease Control (CDC) has complete records.
It is possible the low COVID-19 death race could have something to do with all the open space and good, old-fashioned fresh air in Alaska.
As the Hong Kong researchers noted, “outdoor environments often provide much stronger natural air movement, significantly reducing virus concentrations compared to indoor settings” and “outdoor environments, including large areas of green space, can support safer physical distancing, which reduces infection risks.”
Whatever the case, the researchers said that once they controlled for the many confounding factors – age, obesity, co-morbidities, race, socioeconomic status, access to health care and more – that have been shown to make people more susceptible to COVID-19, they came up with five major correlations between COVID-19 and open space:
- As green space increased, infections rates decreased.
- Forest had the strongest “negative association with infection rates.”
- The connection between green space and reduced infections was greatest in “counties with a moderate level of urbanicity although the association remained significant for all five levels of urbanicity.”
- “The association between forest and infection rates became stronger over the five time periods examined, and was strongest for the most recent time period when infection rates were at their highest.”
- The associations appeared largely linked to forests within a “moderate walking distance,” generally 12.5 to 17.5 minutes, of where people lived.
The study, which has yet to be peer-reviewed, proves nothing. Correlation is not proof of causation no matter how powerful the correlations. But the study suggesting a walk in the woods is good for people does align with others that have shown causative links to activities reducing the risk of COVID-19, such as exercise, or increasing the risk of COVID-19, such as obesity.
“Previous studies have reported that green spaces can promote physical activities, both prior to and during the COVID-19 pandemic,” the researchers wrote. “Numerous studies have found that access to green spaces can
reduce the risk of obesity, and individuals with obesity have been found to be more vulnerable to SARS-CoV-2 infection. Lastly, studies have suggested that physical activities in green spaces can enhance general health and immune function, which may promote resistance to SARS-CoV-2 infection.”
They went on to hypothesize that forested areas might be especially protective against COVID-10 because of their documented role in removing particulates from the air and some developing evidence that forest environments might boost natural immunity.
Breathing in the good stuff
“Several studies have demonstrated a beneficial effect of forest therapy on
human’s weakened immune function,” they wrote. “These effects might be due to plant-derived phytoncides, which are antimicrobial volatile organic compounds (VOCs) that have been shown to reduce blood pressure, alter autonomic activity, and boost immune function by increasing the concentrations and activity of natural killer (NK) cells, among other
Good natural defenses are why an estimated 36 percent of those infected with SARS-CoV-2 never get symptoms. The so-called “asymptomatic” basically get infected without the infection progressing to COVID=19.
Another sizeable segment of the population fights SARS-CoV-2 off well enough that despite developing COVID-19, their symptoms remain mild.
The range of severity of SARS-CoV-2 infections is now well-documented as are the increased risks of serious infection based on age and co-morbidities. The value of open-air has also been known for a long time now.
That the seeming protective value of open spaces has increased as the pandemic has worsened, the researchers said, could be tied to two possible
Increased testing has done a better job of finding the actual number of infections, or there has been a shift from infections “spread mainly via intimate social gatherings or institutional activities, such as family gatherings, parties of close friends, or school activities” to infections spreading at a broader community level.
The researchers added that a lot more work needs to be done to pin down the apparent link between open space and good health, but in some regards the study reflects what was learned during the last great, global pandemic – the Spanish Flu – almost exactly a century ago.
And that was that fresh air matters.
The newest study is in line with that old, old finding and comes at a time when another study is adding to the evidence of the aerosol spread of SARS-CoV-2.
A study accepted last week by Clinical Infectious Diseases, a peer-reviewed publication, found that when people infected with SARS-CoV-2 exhaled into a breath collector “fine aerosols constituted 85 percent of the viral load.”
Most masks don’t block fine aerosols, as Dr. Michael Osterholm, the director of the Center for Infectious Disease, Research and Policy (CIDRAP) at the University of Minnesota told both CNN and PBS last week. Osterholm is one of the country’s most respected authorities on infectious diseases.
His comments were largely ignored by the mainstream media and the CNN video is now almost impossible to find using Google, but the transcript can still be found here: https://transcripts.cnn.com/show/ip/date/2021-08-02/segment/01
In it, Osterholm noted, that “if you’re in the upper Midwest, right now, anybody who’s wearing their face cloth covering can tell you, they can smell all the smoke that we’re still getting.”
The smoke smell is transmitted by fine aerosols going through the mask. SARS-CoV-2 viruses are small and can do the same thing. Osterholm took his comments on masks even further on PBS where he accused public-health officials of doing “a disservice to the public.
“When you actually look at face clothing coverings, those clothing pieces hanging over your face, they actually only have very limited impact on reducing the amount of virus that you inhale or exhale out.
“And, in fact, studies that have been done show that if an individual might get infected within 15 minutes in a room, by time and concentration of the virus in the room, add a face clothing covering (and) you only get about five more minutes of protection.
“I’ve been really disappointed with my colleagues in public health for not being more clear about what masking can or cannot do.”
Osterholm said that if masking is expected to do much, people need to equip themselves with N-95 respirators that block particles down to the size of 0.1 to 0.3 microns.
His comments come at a time when the discussion of SARS-CoV-2 transmission is shifting from droplets, first believed the chief carrier of the virus, to aerosols.
Droplets, basically human spittle from talking or singing, are generally considered to be five microns or larger.
“Cloth masks not only effectively block most large droplets (i.e., 20-30 microns and larger), but they can also block the exhalation of fine droplets and particles (also often referred to as aerosols) smaller than 10 microns,” according to the CDC.
How well various masks block particles smaller than 10 microns is, however, unclear, and a new study conducted by researchers in Singapore, is reporting that it now appears that when people infected with SARS-CoV-2 shed virus into the air 85 percent of the dangerous particles are 5 microns in size or smaller.
“Our study demonstrates that SARS-CoV-2 can be aerosolized in the absence of coughing, sneezing, and aerosol-generating medical procedures,” those researchers reported. “More than half of our study participants emitted
detectable levels of SARS-CoV-2 RNA in respiratory aerosols,” and some emitted as much virus while talking as singing, which has been previously red-flagged as a dangerous activity.
“Our results demonstrate the potential for fine respiratory aerosols to play an important role in community transmission of SARS-CoV-2, which is in agreement with other expert views suggesting that SARS-CoV-2 transmission
events are driven by the airborne route and could explain the difficulty in containing the virus,” the researchers concluded.
They recommended continuing universal masking and social distancing while improving room ventilation and adding high-efficiency particulate air (HEPA) cleaners in indoor environments. They also suggested the use of “upper-room ultraviolet air disinfection, and the use of fans to control airflow patterns within a space.
“For situations involving talking, determining airflow patterns and minimizing exposure through seating and furniture configurations, distancing, and air movement alteration (such as fans, including desk fans) would be practical options,” they wrote.
Given the difficulty of studying sub-microscopic-size particles, the study, unfortunately, did not break down the size of the most dangerous SARS-CoV-2 aerosols. The virus itself is reported to measure about 0.1 microns, but it is attached to water vapor or dust of some size when exhaled.
The Singapore exhalation study did not require participants to breathe through masks, so it is unknown what percentage of small aerosols would have passed through a mask or whether large particles blocked by the mask would have been aerosolized by the force of exhalation.
Osterholm and others have noted that in many places infection rates only went up after universal masking was instituted. A widely ignored study out of the University of Vermont might have explained why that happened.
The study published in the peer-reviewed JMIR Public Health & Surveillance in May reported that as the number of contacts people had with each other went up so did the number of COVID-19 cases whether people were masked or unmasked.
“We found that seeing more children per day does not increase the probability of getting COVID-19,” they wrote, “but having more daily contact with adults and older adults does. We further identified factors that have an increasing effect on the number of daily contacts, such as living in an apartment and wearing a mask.”
The latter two factors, living in an apartment and wearing a mask, might help explain the extraordinarily high infection and death rates in NYC.