Almost 300 years ago a brave scientist boldly stated that everything can be described as waves. It took mathematicians another 200 years to prove that Joseph Fourier, the bold scientist, had it right. I am comforted by this fact while the Covid-19 pandemic appears to grow without bounds. And yet, bounds do exist, because Fourier states that what goes up must come down. This includes the global Covid-19 pandemic of 2020/21 as well as the Influenza pandemic of 1918/19. The latter had three distinct peaks in the United Kingdom that varied both in amplitude and duration:
This pandemic of 100 years ago came in three distinct pulses in the spring of 1918, in the fall of 1918, and in the winter of 1919. The graph shows that during the first wave about 0.5% of all infected people died while the second and third wave were more deadly with 2.5% and 1.3% fatality rates. These rates are somewhat similar to those we see today with Covid-19, but there is much we do not yet know.
We do not yet know, for example, how long it will take for the Covid-19 waves to pass through populations. We do not know the amplitude of the waves either, because it all depends on how well we distance ourselves from each other both now and into the future to minimize transmission of the virus. There is no control, yet, because no vaccine exist, but smart distancing will impact how many people will get infected (the amplitude) over time (the period).
These two factors (amplitude and duration) will determine how many of our friends, partners, parents, brothers, and sisters we will lose to the virus. As the German Chancellor Angela Merkel said yesterday: “Im Moment ist nur Abstand Ausdruck von Fuersorge,” which translates as “At the moment only distance is an expression of care.”
Waves change as they propagate from one medium to another. As ocean wave forms move from deep to shallow water they change both amplitude and speed until they eventually break. I view today’s Covid-19 waves in a similar way.
Covid-19 waves will propagate through all societies on our planet, but they will propagate differently in different regions, countries, and societies. Amplitudes, periods, and propagation speeds will differ. Some of this is already visible by global statistics that are collected and shared in real time:
The spread of the virus in China differs from that in South Korea which differs from that in Iran, Italy, Germany, and the United States. Different political systems, different skills of and trust in governments, and different personal behaviors all provide a different medium within which these waves propagate and, eventually, will dissipate.
This is day-8 for me and my wife to distance ourselves from our friends, family, and neighbors. We are fine. My wife turns the bedroom into a painted mural while I read and write at home and spent much time in the spring garden. It slowly sinks in, that this will not be over next week or next month. The goal is to make the amplitude as small as possible by spreading the period out as long as possible which will allow our hospitals, nurses, and doctors to provide the best care for those who need it. As a wise woman said yesterday: “At the moment only distance is an expression of care.”
Taubenberger, J.K. and D.M. Morens: 1918 Influenza: The mother of all pandemics, Emerging Infectious Diseases, www.cdc.gov/eid, 12 (1), 2006.”