Let’s start with a medical dictionary definition of a virus: “One of a group of minute infectious agents…characterized by a lack of independent metabolism and by the ability to replicate only within living host cells. Like living organisms, they are able to reproduce with genetic continuity and the possibility of mutation.” Viruses are responsible for multiple human diseases including polio, mumps, measles, rubella, influenza, and hepatitis — many of which we see only rarely since the advent of immunizations, which produce a lasting immune response without causing infection. Hepatitis B and HPV (human papilloma virus) are examples of viruses that can sometimes cause cancer (cancer of the liver and cervix, respectively).
Coronaviruses are a family of viruses that cause disease in mammals and birds. In humans, coronaviruses cause diseases that vary from the common cold to potentially lethal diseases such as SARS, MERS, and the new human disease called COVID-19. The virus that causes COVID-19 is officially called SARS-CoV-2 — the 2 because it’s the second SARS virus that has been discovered.
SARS-CoV-2 originated in China. At first it was thought to have originated in a market in Wuhan, but now some experts think it originated in bats. Human-to-human transmission occurs by respiratory droplets when someone within 6 feet of another person coughs or sneezes. The virus can live on various surfaces from minutes to days, depending on the surface. If someone touches a surface with live virus particles, and then they touch their face, the virus can enter their respiratory tract via their nose or mouth. Once in a person’s respiratory tract, the virus sometimes travels down the trachea (windpipe) to the lungs.
The trachea branches multiple times and at the ends of the final, smallest branches are minute air sacs called alveoli. There are 600 million alveoli in a person’s lungs, and this is where oxygen transfers from the lungs into the bloodstream, and carbon dioxide exits. The CoV-2 replicates in the lungs, and the millions of viral particles that result attack the alveoli, causing an inflammatory response, which in turn results in swelling and fluid in and around the alveoli. Oxygen and carbon dioxide exchange become impaired, and the lungs become stiff and fail to contract and expand easily with breathing. This condition is called acute respiratory distress syndrome (ARDS).
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Not all people with COVID-19 develop serious illness, and some probably remain without symptoms at all (it’s hard to know how many because of lack of adequate testing in the U.S.). However, when a COVID-19 patient start to crash, they can spiral downhill within hours. Soon they are struggling to breath and need to be in the ICU, with a breathing tube down their trachea, attached to a ventilator. Even if this treatment is instituted rapidly, a significant percentage of patients on a ventilator end up dying from total organ failure — their organs don’t get adequate oxygen.
Some countries have this epidemic under control, but anyone keeping up with this pandemic knows that COVID-19 deaths in the U.S. are skyrocketing, as predicted by public health experts as long ago as early February. It’s frustrating for those of us in the medical field that there are still not enough ventilators in many parts of the country, which will result in unnecessary deaths. And even at this stage of the pandemic, there aren’t enough masks and other protective gear for health care providers, which is resulting in provider sickness, death and burnout.
The countries that have handled this pandemic most successfully — South Korea, China, Singapore, Japan — had a coordinated national approach driven by public health officials rather than politicians. Leaders in those countries foresaw what was coming — partly from past experience with other pandemics that we all should have learned from such as SARS — and immediately did everything they could to bring the pandemic under control through public health measures. They tested a lot, and didn’t lack for equipment such as respirators for patients, or protective gear for health care providers. Unfortunately, our initial slow and haphazard approach is manifesting itself in our death statistics.
Greg Feinsinger, M.D. is a retired family physician who has a nonprofit: Prevention and Treatment of Disease Through Nutrition.