But when I came to the section regarding ritual purity, the laws pertaining to the mikveh seemed fairly straightforward. But the laws regarding ritual contamination left me wondering about the characteristics of ritual contamination. I wondered: Did the rabbis think of ritual impurity as a spiritual or as a physical phenomenon? This question bothered me for many years and decades. The rituals of handwashing originated from these Levitical laws and historically, handwashing helped prevent the spread of contagions. To this day, the pious Jew almost instinctively washes his/her hands several times in the course of the day.
In this week's Parsha Tazria and Metzorah, considerable space is dedicated to the theme of the problem of ritual uncleanness with respect to the ancient dreaded disease of leprosy—a disease that does not kill but disfigures the victim. The ancients practiced social-distancing because they did not know how to deal with a threatening disease that might spread upon close contact with others.
In Levitical literature, uncleanness describes ritual uncleanness as a substance that can cling to a person or thing and may be transmitted to others in a variety of ways. The Mishnah creates a hierarchy of ritual contamination. The “grandfather” of all uncleanness is the human corpse. Ritual uncleanness can be transmitted in a variety of ways. The Mishnah distinguishes between the primary source of impurity, commonly referred to as (אַב הַטֻּמְאָה), and from there it imparts uncleanness to the object that is infected. The latter is what is sometimes called, a “child of uncleanness” (וְלַד הַטֻּמְאָה).
Examples of the former include anyone who has been in contact with the dead—either directly or indirectly, e.g., sharing space under the same roof with a corpse. An animal carcass, the blood of couches, beds, foods, and drinks; it includes being in touch with lepers, or human bones—each of which is considered as a primary transmitter of ritual uncleanness. Thus, we have primary sources of ritual contamination, along with second, third, and fourth degrees of uncleanness. Men, hands, vessels, and clothes are infected only directly through contact with the dead, or with a leper.
Secular or non-sacrificial meats and drinks (חֻלִּין,) are susceptible to second-degree infection. First-fruits, priestly tithes, are affected only to the third degree, and sacrifices to the fourth. The intensity of infection weakens a stage with each transmission. The ancient Greeks were no stranger to the concept of ritual pollution, a term they called μίασμα(miasma), believed to be a physical contagion that is airborne. This pollution especially occurs when there is a murder or any kind of heinous crime, thus leaving those responsible of taint pollution. These laws probably make little sense to a modern Jew. If the most Orthodox Jew were to travel in a time machine to the time of the Second Temple, odds are s/he would feel completely out of place in a Jewish society that took the purity laws seriously.
As with the Mishnaic laws of uncleanness, the parameters concerning how the COVID-19 virus can live in the air and on the surfaces. One study from the John Hopkins School of Medicine found the virus is viable for up to 72 hours on plastics, 48 hours on stainless steel, 24 hours on cardboard, and 4 hours on copper. The virus has also detectable in the air for three hours. The virus is purported capable of lasting on plastic for 72 hours. According to the New England Journal of Medicine, COVID-19 can be detected in the air for 3 hours. Nevertheless, one is more likely to catch the infection through the air than to someone infecting them off of a surface. Cleaning the surfaces with disinfectant or soap is very effective because once the oily surface coat of the virus is disabled, there is no way the virus can infect a host cell.
Objects to be concerned about include tables, doorknobs, light switches, countertops, handles, desks, phones, keyboards, toilets, faucets, and sinks. Avoid touching high-contact surfaces in public. Handwashing with a strong disinfectant soap and water for at least 20 seconds upon returning home, or from public places such as a bank or grocery store. Social distancing requires there be a distance of six feet between people standing in a line.[i]
Although these laws have not played a dominant role in Jewish life for over 2000 years, the guidelines bear a striking resemblance to the precautions we now observe in stemming from this pandemic. Note that in the days of the Temple, rabbinic tradition imposed social distancing in preventing people who were ritually unclean from entering the Temple.
According to Maimonides, the laws governing ceremonial uncleanness are designed to help heighten the faith community’s respect when entering the Temple. But today, these ancient rules of uncleanness take on an altogether new meaning in the age of the COVID-19 pandemic.
 Taharoth, 1, 5.
 Kelim, 1.
 Yadaim 3:1,