Viruses, strictly speaking, are not alive. They are tiny sets of genes bundled within protein shells, with one singular function — to replicate. Lacking cells or other common features of living organisms, viruses are parasitic zombies. They infect living cells, hijack the genetic machinery, and mass-produce replicas of themselves. (A single sneeze can release 100,000 viruses into the air.) The common cold is a virus, and so are influenza, measles, HIV, and Ebola. The new coronavirus, Covid-19, has joined the list of humanity's viral scourges, after apparently jumping species from its original host, bats. It has sickened more than 80,000 people and, infectious-disease experts say, it's coming to America. One way or another, it will affect all of our lives.
As Covid-19 relentlessly advances, there is much scientists and doctors do not yet understand. Infection produces widely varying responses. Some people have no symptoms, but can still transmit the virus to others. A majority suffer only mild respiratory distress. Others become severely sick, with flu-like aches and high fever and pneumonia. Deaths occur when the infections trigger an out-of-control immune response, creating a "cytokine storm" that inflames and shuts down the lungs. Scientists estimate a mortality rate of 2 to 3 percent. If there are major outbreaks in the U.S., authorities may discourage people from congregating in crowds, and may temporarily shut schools and curtail travel. The economy could take a significant hit. Covid-19 may even have an unpredictable impact on the presidential race. Americans tend to overreact to such disruptions; protected by our oceans and relative affluence, we expect to be exempt from problems affecting places like China and Italy. Now we face a mindless invader thousands of times smaller than a grain of sand — one that knows no national boundaries. Covid-19 will test our strength, our social cohesion, and our leaders.