The responseĪs we are all painfully learning, social distancing involves measures to keep people apart as a way to slow the spread of a virus to which everyone is susceptible. With World War I raging, the stage was set for a clash between biology and history. (Influenza A, the type of influenza that causes pandemics, was not identified as a virus until 1933, well after the pandemic was over.) Second, the world was in the midst of a war. Best guesses at the time were that a bacterium, called Haemophilus influenzae, was causing the severe illness being witnessed. First, influenza virus had not yet been identified. In 1918, the situation during the influenza pandemic was worse for two reasons. Like in the current situation, the virus was known but treatments were limited and prevention, in the form of a vaccine, was not an option. In the 1950s, children were kept from pools and churches in an effort to stave off polio infections. We also don’t have treatments or vaccines, so we are left with long-forgotten methods of trying to stem the spread of this disease, like social distancing. We do not know how long from exposure to infection, average length of infection, etc. But, COVID-19 is not influenza, which means we do not have the history of experience that we have with the family of influenza viruses. When explaining COVID-19, the antigenic shift of influenza that causes a pandemic offers a familiar example. (See this Vaccine Makers Project animation, “Antigenic Drift: How the Influenza Virus Adapts.”) Because all people are susceptible, when these two things happen, the stage is set for a pandemic to occur. Second, it can be spread from one person to another. First, it is capable of infecting people and causing illness or death.

The new virus becomes a concern if it has two characteristics. Indeed, in some conversations, we go so far as to describe the difference between an epidemic and a pandemic – the former being those small annual changes (antigenic drift) and the latter, a larger event caused when the genomes of bird, human or pig influenza viruses combine to form a new influenza virus (antigenic shift). We all know influenza virus changes regularly, as we point to this characteristic of the virus when we describe the need for annual flu vaccination. As we all come to terms with a new, and hopefully short, definition of “normal” during the COVID-19 pandemic, many may be wondering why this virus is being treated differently and why “social distancing” has become a recent buzz word.Ī look back to a century ago can offer some insights - both regarding what we can learn from our ancestors as well as, perhaps, a sense of “walking in their shoes” for a moment.

Antigenic shift covid 19