Some characteristics of the COVID-19 virus are known, but far more are still a mystery. One of the most mystifying is why some Pennsylvania counties have recorded no deaths, while others, especially in our area, are considered among the state’s hot spots.

Most epidemiologists agree that there may be no single reason why some counties have been hard hit while others are relatively free of cases.

Among Pennsylvania’s 67 counties, 18 have recorded no deaths to date; another 12 have had just one death attributed to the virus.

Health experts have concluded that counties with more densely populated communities have shown the most cases and the most deaths, but that is just one mitigating factor.

Health Secretary, Dr. Rachel Levine, says that travel between some areas and other hot spots such as New York City and northern New Jersey also can be a major factor in the spread of the infection. Monroe County, Allentown and Hazleton are often cited as examples.

There have been several spectacular examples of how one infected person can turn into a super-spreader by attending a crowded social occasion then passing along the virus to family members, friends and others with whom he or she comes into contact - a phenomenon known as “community spread.”

One of the most publicized events of this nature was when an infected guest attended a large funeral in Albany, Georgia. Other examples included the infection of 634 people aboard a Princess cruise line off the coast of Japan by a single passenger, and when a 61-year-old woman attended church services in South Korea and became the catalyst in the spread of the virus to hundreds of congregants, who then passed it along to thousands of others.

Because an infected person doesn’t have any symptoms for a week or more, if ever, the virus can spread undetected and seemingly at random.

In Pennsylvania, the counties with no deaths from COVID-19 as of Wednesday were: Blair, Cameron, Clearfield, Clinton, Crawford, Elk, Forest, Fulton, Huntingdon, Jefferson, McKean, Mifflin, Montour, Northumberland, Potter, Sullivan, Venango and Warren. Eight of these have reported fewer than 10 cases each.

Despite the absence of deaths, four of these counties will not be among the first to have a partial reopening on Friday. They are: Blair, Fulton, Huntingdon and Mifflin. Fulton had reported just six cases.

It is this kind of decision-making by Gov. Tom Wolf and his administration that is driving some lawmakers in these counties crazy.

Sen. Judy Ward, a Republican whose district includes Blair and Fulton counties, said it is troubling that these two counties were not included because of their low infection rates and no deaths.

Blair County, with a population of 122,000, is the largest of the 19 counties with no deaths; Fulton, with a population of 14,000, is one of the smallest.

In Blair County, about 50 miles southwest of State College, there had been just 25 reported cases of COVID-19, but in Carbon County, with a population of less than half of Blair’s, there had been 186 reported cases with 16 deaths.

Health Secretary Levine said the number of cases in a county is just one of the considered metrics in determining a switch from red to yellow status.

One possibility why these counties have not been more severely impacted is because the virus hasn’t had the community spread that larger, more densely populated counties have had nor have they had traffic to and from hot spots.

If this is true, why is there such a dramatic difference in the number of cases between Eastern Pennsylvania and Western Pennsylvania? Philadelphia and its suburban counties are among the state’s highest in the number of cases, while far fewer cases have been reported in Allegheny and surrounding counties.

The question of why COVID-19 has been so widespread in some counties, such as Monroe, Lehigh and Northampton in our area, yet left others less affected has led to much speculation but no unanimous conclusions.

This question is graphically illustrated by this statistic: Allegheny County, including Pittsburgh, has a population of 1.2 million and has had 1,394 COVID-19 cases and 111 deaths, while Monroe, with a population of 170,000, has had 1,190 cases and 60 deaths. Luzerne County, with about one-quarter the number of people compared to Allegheny, has had almost twice as many cases (2,306) and nearly as many deaths (107). Northampton’s population also is one-quarter that of Allegheny’s but has had more cases (2,313) and more deaths (122).

According to The New York Times, there are hundreds of studies trying to find out how genetics, pre-existing conditions, demographics and travel patterns might affect the incidence and spread of the virus.

One big question epidemiologists want to answer involves the weather. The Spanish flu, which devastated the United States and much of the rest of the world in 1918-19, went into decline in the summer months only to come back with a vengeance in the fall.

The director of the Harvard Global Health Research Institute, Dr. Ashish Jha, said that if we were in a baseball game, we would now be in the second inning of a nine-inning game.

By Bruce Frassinelli | tneditor@tnonline.com