A ‘Second Wave’ is Not Inevitable

Even though we’re doing well, it’s not the time to let down our guard; it’s about being careful, cautious and prepared.

The numbers of COVID-19 cases are now very low in Austria – just 418 active cases; daily death rate 0 to 1 – and we’ve begun to feel safe.  Things are reopening, and we are getting back to something like normal life.

It is just when you let down your guard, we are warned, that there could be a resurgence of infections. That’s what’s meant by a second wave, one that could be one large one or a series of ripples with small outbreaks or clusters, even in areas where there were no previous cases. And although Austria has done remarkably well containing the first wave of COVID-19, we cannot be complacent. It only takes one SARS-CoV-2 infected person to start an outbreak and that means that we should seriously consider the possibility for a second wave of COVID-19 and the need to return to strict general measures.

Still a large second wave is not inevitable: There are things that we can do that could lessen it’s likelihood or even prevent it.

Predictions based on experience

History and computer modeling of previous data predict the probability of second and more waves following any epidemic. In other words, experience from past pandemics indicates that second waves are predictable. There are many examples, following outbreaks of Influenza A dating back to 1889, or the Spanish flu in 1918 with several secondary waves over two years.

Recent events confirm these predictions are correct, as we see new outbreaks in Singapore, South Korea and Hong Kong, while computer models also predicted a spike in cases and deaths in the southern hemisphere as the northern hemisphere’s pandemic receded.

Common sense makes it tough to understand why we should expect a second wave in Austria; there are only a few cases of COVID-19 now, the virus is gone and the pandemic is almost over. But, the pandemic is not over and rushing out of lockdown and getting back to normal life can be a recipe for new waves of cases.

Relaxing social distancing measures too quickly and permitting “superspreader” events are the leading causes for multiple waves. The COVID-19 outbreak in Ischgl showed us how effective a superspreader could be. Another recent example of a superspreader occurred in South Korea when on one night, a man visited three nightclubs and inadvertently infected 54 people. Imagine how quickly an outbreak can grow when each of the 54 people infects one other person, and these people infect one other person.

The exponential growth rate from a superspreader event means a high number of cases because of the doubling of cases over time. An example for helping to understand this type of growth, let’s say that COVID-19 cases double in number every day. That means that the first case on day one would become two cases on day two and continue to double resulting in 4 (day 3), 8 (day 4), 16 (day 5), 32 (day 6), 64 (day 7), 128 (day 8), 256 (day 9), 512 (day 10), 1024 (day 11), 2048 (day 12), 4096 (day 13), 8192 (day 14) cases in 14 days. In other words, within two weeks, one single case could explode into over eight thousand. The exponential growth of COVID-19 will occur after a superspreader event with these three conditions: one infected person; infected and uninfected people in close contact; and many uninfected (unimmunized) people.

Hard questions and educated guesses

The “when” is hard to answer: It is really too early to say. The SARS-CoV-2 virus might be seasonal like flu, which typically arrives in the autumn and peaks in the winter. But COVID-19 could return in the summer or will wait for cooler weather when people tend to be in close contact. We might have had a break over the summer based on the behavior of other coronaviruses that don’t like the summer months, but SARS-CoV-2 seems able to resist high temperatures and humidity as the spread through tropical countries shows us.

As to whether it will be worse, again, the answer is, we don’t know. It depends partly on the measures we used the first time. A good example of foresight was the Australian travel ban with China that started on Feb 1st, 2020. Because of this, and a slow reopening from lockdown, Australia had few cases and deaths and is not expecting a severe second wave.

The magnitude of a second wave also depends on maintaining containment and mitigation measures, and having “herd” immunity in a high percentage of the population.

A second COVID-19 wave will also be worse if it happens at the same time as a flu outbreak. The two infections together make more sick people, which overloads the hospitals. Also, co-infection with the two viruses can cause more severe illness thereby increasing the death toll.

Another possibility is that a genetic mutation of SARS-CoV-2 could cause a deadlier strain, similar to the second wave of the Spanish flu in 1918. But genetic mutations could also make COVID-19 less virulent, which makes predicting the severity of a second wave difficult.

A second wave is not inevitable

A second wave is not inevitable when the majority (greater than 60%) of the population is immune to the virus through natural infection and an effective vaccination program. However, without herd immunity and recent evidence that some recovered SARS-CoV-2 patients might not have lasting immunity, a second wave is possible.

The good news is that we can substantially reduce the magnitude of a second wave or prevent it by social distancing practices, wearing face masks, hand washing, and limiting the number of superspreader events.

Mass testing for active cases and for people who have already had COVID-19 along with contact tracing, rapid identification of new clusters and immediate isolation of potentially infected people will be crucial for preventing the next wave.

If we can’t avoid the second wave, we need to prepare for it, and that means ensuring that there’s an ample supply of personal protective equipment, ventilators, medications, testing kits, and qualified healthcare workers.

The power of low tech

Please don’t underestimate your role in preventing a resurgence of COVID-19. The simplest, low-tech measures are more powerful than you think – keeping your distance, wearing a mask and washing or sanitizing your hands must be the “new normal” for the foreseeable future. 

So we have to worry about the second wave? Not if we are careful, cautious and prepared.

A few tips to help prevent and/or prepare for a second wave

  • If you’ve been in contact with someone you know has COVID-19, or you think that you have symptoms, call the coronavirus hotline and immediately isolate yourself.
  • Keep washing or sanitizing your hands, and don’t touch your face if your hands aren’t clean.
  • Stock up on face masks and wear them in public and crowded places.
  • Get your yearly flu shot to reduce your risk of being sick with the flu and COVID-19.
  • Work from home as much as you can because there is less chance of contracting the virus when you’re home, and fewer people in public places also reduce viral spread.
  • Avoid crowds and superspreader events.
  • Find a new way to greet friends and family without touching them by waving, putting your hand on heart, blowing a kiss to them, air-kissing, or bowing.

(Foto: Silas Baisch on Unsplash)

Dr. Michelle Epstein
Michelle Epstein is a medical doctor graduated from the University of Alberta in Canada, who has specialised in Internal Medicine at the University of British Columbia and Allergy and Clinical Immunology at Yale University. Since 2004, she has been a Lab Leader at the Medical University of Vienna’s Division of Immunology.

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