There’s been much speculation about if and when a second coronavirus wave will come crashing down on us, and whether it has the potential to be more severe than the first crest.
After all, that’s what unfolded with past respiratory infections like the 1918 flu pandemic, which had a second wave far more devastating and fatal than the first.
But epidemiologists — the people who study the patterns and causes of diseases — warn against assuming that COVID-19 will behave like the infectious diseases we’ve seen before. This is a brand-new virus and it’s not clear this pandemic will even see a second wave.
What’s more likely, several epidemiologists who spoke to HuffPost suggested, is that the first wave will continue to swell, with daily cases and death counts rising and falling in particular areas, until the population eventually achieves herd immunity – which seems unlikely without a widely available vaccine.
That said, we’ve never dealt with this specific virus before, so we really don’t know what the pandemic will look like three months from now. “We’re in totally uncharted waters here,” said Anne Rimoin, a professor of epidemiology at the UCLA Fielding School of Public Health.
Here’s what the epidemiologists think about a second wave:
Why do second waves happen?
Let’s first get into what we know about second waves in general by looking at our old friend influenza. The flu is a seasonal illness. It spreads well in cold, dry air, especially when people huddle together indoors during the winter.
“We see first and second waves with those because seasonally, they go away,” said Christine Johnson, a University of California, Davis professor of epidemiology and researcher on the U.S. Agency for International Development’s Emerging Pandemic Threats PREDICT project.
The flu virus also mutates easily. Each year, we see new variations of the flu, and second and third waves in a given flu season are often caused by strains different from the one behind the first wave. We just saw this in the 2019-2020 flu season: B strains struck first, then A-strain variations came in a second wave.
But we’re dealing with COVID-19, not the flu — and that’s an important distinction to make. Jennifer Horney, a disaster epidemiologist and founding director of the University of Delaware’s epidemiology program, said that predicting a new virus’s behavior based on other illnesses risks a “false expectations paradox.”
Recent flu pandemics — like the avian influenza in 2005 and the H1N1 outbreak in 2009 — may have given us the wrong idea about how COVID-19 will play out, Horney said. Those past outbreaks came in multiple waves because of how their flu viruses behaved and were transmitted.
Epidemiologists are doing their best with past models and adjusting as we learn more about this coronavirus. But ultimately, the COVID-19 virus has its own viral behavior patterns. “Since it’s novel, we don’t know what it’s going to look like yet,” Horney said.
Here’s what could happen with COVID-19
It’s hard to say for certain, but here’s what epidemiologists think could occur as time passes.
We know this coronavirus spreads easily from person to person. In the summer months, people are outside more and able to stay further apart — this definitely decreases transmission, according to Johnson. But in the fall and winter, people will take more activities indoors and the coronavirus could thrive in enclosed environments.
The closure of schools and the restrictions on businesses this spring has also kept people apart, just as the reopenings will let us congregate again.
“When schools reopen and people are going back to the office – a lot of people are saying we’ll go back to the office after Labor Day – you could see a big spike in cases again because you’re going to have people coming together,” Rimoin said.
Unfortunately, we don’t know how the coronavirus responds to changes in the weather. While the flu ebbs and flows with the seasons, right now there’s no proof that COVID-19 does the same. Just look at what’s going down in hot-weather places like Arizona, Florida and Texas. (Not to mention Brazil and Peru.)
The coronavirus has also mutated already, but not as rapidly and drastically as the flu virus. Rimoin said a new mutation could potentially cause a bigger wave but so far this virus hasn’t mutated in a way indicating that’ll happen.
Lastly, for a second wave to even occur, the first wave needs to be controlled and new cases need to be near zero for weeks at a time, Johnson said. Some countries have achieved this — including New Zealand and Iceland — but the U.S. has not even come close. Coronavirus cases are rising in nearly half of U.S. states, and as states continue to reopen, all the experts who spoke to HuffPost expect cases to increase.
In other words, the current wave will keep coming in. “We’re sort of on a very slow rollercoaster,” Horney said.
Rimoin added that it’ll likely continue as such until we have herd immunity – when the great majority of the population is immune to the disease. Realistically, we can’t count on achieving herd immunity without a vaccine.
“Without a vaccine, getting to herd immunity just through prior infections that offer antibody protection is pretty impossible,” Horney said.
Bottom line: We’ve never seen COVID-19 before
The truth is we really can’t say what’s going to happen next. We can create models and make predictions, but so much about COVID-19 remains unknown.
“I think we would all love to know what’s going to happen [but] we’ve never been in this situation before,” Rimoin said.
We need to keep social distancing, wearing our masks and washing our hands to curb this epidemic. Areas that see greater surges in new cases may need to consider shutting things down again to avoid overwhelming their local health care systems.
“I understand some of the fatigue and exhaustion and the need for us to have societal well-being and economic progress,” Johnson said. “But the virus doesn’t abide by any of those other concerns that we have.”
Experts are still learning about the novel coronavirus. The information in this story is what was known or available as of press time, but it’s possible guidance around COVID-19 could change as scientists discover more about the virus. Please check the Centers for Disease Control and Prevention for the most updated recommendations.