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Why public health officials sound more worried about the coronavirus than the seasonal flu
An epidemiologist explains.
At the same time, the seasonal influenza, known as the flu, causes severe illness in between 3 million and 5 million people, with hundreds of thousands of deaths every year worldwide.
With so many fewer cases than the flu, what explains the dramatic response to COVID-19 and worry around the globe? And how would a person know whether seasonal influenza-like symptoms are COVID-19?
As an epidemiologist, here's how I look at these questions.
Difficult to distinguish
The first thing to realize is that the emergence of the novel coronavirus isn't a rare "black swan" event. Rather, this is a product of evolution; there have been about 40 new, infectious diseases discovered globally since the 1970s, with pathogens often jumping from animals to humans.
Detecting who has this new virus becomes a key public health challenge, which is made harder because it's the season for another virus – influenza. And in the U.S., there is a shortage of local laboratories able to test for the coronavirus virus in humans.
Influenza, by contrast, is far more familiar to public health researchers and doctors, and thus more predictable. It can occur anytime during the year in the U.S., but it typically begins in September and can go into May of the following year. While the peak of cases in the U.S. fluctuates, it typically occurs in February when the disease is widespread across the country.
If a new disease emerges during influenza season and has different signs and symptoms than the influenza, then it is easier to detect and track in the human population. However, if the signs and symptoms overlap, as they do with flu and COVID-19, detection is much more difficult for the public health, medical and the lay population.
COVID-19 produces signs and symptoms that are similar to influenza, which makes it difficult to distinguish between the two. COVID-19 can cause fever, cough, body aches, fatigue and, occasionally, vomiting and diarrhea; both can cause pneumonia as well.
Speed of spread
Currently one of the biggest differences between seasonal influenza and COVID-19 is the incubation period – that is, the time from exposure to development of signs and symptoms. For seasonal influenza, the incubation period ranges from one to four days, but in some instances, people may be contagious a day before symptoms appear and as long as five to seven days after symptoms start. COVID-19's incubation period ranges from 2-14 days, which is up to three times longer than influenza.
Also, COVID-19 is more contagious than seasonal influenza. The average person, even with mild symptoms, is likely to spread the disease to more than two people. By contrast, the seasonal flu's rate is roughly half.
Another significant challenge with influenza and COVID-19 is that they both can have mild infections. People with more mild disease are less likely to seek diagnosis and care, but are still considered infectious and able to transmit the disease person to person.
The death rate of the seasonal flu varies year to year but is about 0.1%, compared to about 2% for COVID-19. The disastrous 1918 influenza epidemic, known as the "Spanish flu," had a death rate of about 2.5%.
Finally, one of the biggest concerns for COVID-19 is asymptomatic infections. People who are infected with the virus may be able to transmit the infection, and yet they themselves don't have any signs or symptoms of disease. This represents a challenge because it would be difficult to identify persons that need to be tested for the disease since they have no signs or symptoms, but their ability to transmit the disease would allow for amplification in a naive, or uninfected, population.
No vaccine available for COVID-19
Unlike influenza, COVID-19 does not have a vaccine or medication people can take to protect themselves and it is believed that everyone is susceptible.
There are a number of efforts to develop treatments for COVID-19, but nothing is yet approved. Vaccines are also being pursued, but a vaccine for COVID-19 will not be ready for several months.
Getting the vaccine for the seasonal flu can actually be helpful for medical professionals. Since the signs and symptoms are similar, if everyone were to be vaccinated against the flu, fewer people would have the flu, thus making it easier to detect another disease with similar symptoms. The faster it is identified, the faster public health and the medical community can respond to minimize the spread of disease.
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An open letter predicts that a massive wall of rock is about to plunge into Barry Arm Fjord in Alaska.
- A remote area visited by tourists and cruises, and home to fishing villages, is about to be visited by a devastating tsunami.
- A wall of rock exposed by a receding glacier is about crash into the waters below.
- Glaciers hold such areas together — and when they're gone, bad stuff can be left behind.
The Barry Glacier gives its name to Alaska's Barry Arm Fjord, and a new open letter forecasts trouble ahead.
Thanks to global warming, the glacier has been retreating, so far removing two-thirds of its support for a steep mile-long slope, or scarp, containing perhaps 500 million cubic meters of material. (Think the Hoover Dam times several hundred.) The slope has been moving slowly since 1957, but scientists say it's become an avalanche waiting to happen, maybe within the next year, and likely within 20. When it does come crashing down into the fjord, it could set in motion a frightening tsunami overwhelming the fjord's normally peaceful waters .
The Barry Arm Fjord
Camping on the fjord's Black Sand Beach
Image source: Matt Zimmerman
The Barry Arm Fjord is a stretch of water between the Harriman Fjord and the Port Wills Fjord, located at the northwest corner of the well-known Prince William Sound. It's a beautiful area, home to a few hundred people supporting the local fishing industry, and it's also a popular destination for tourists — its Black Sand Beach is one of Alaska's most scenic — and cruise ships.
Not Alaska’s first watery rodeo, but likely the biggest
Image source: whrc.org
There have been at least two similar events in the state's recent history, though not on such a massive scale. On July 9, 1958, an earthquake nearby caused 40 million cubic yards of rock to suddenly slide 2,000 feet down into Lituya Bay, producing a tsunami whose peak waves reportedly reached 1,720 feet in height. By the time the wall of water reached the mouth of the bay, it was still 75 feet high. At Taan Fjord in 2015, a landslide caused a tsunami that crested at 600 feet. Both of these events thankfully occurred in sparsely populated areas, so few fatalities occurred.
The Barry Arm event will be larger than either of these by far.
"This is an enormous slope — the mass that could fail weighs over a billion tonnes," said geologist Dave Petley, speaking to Earther. "The internal structure of that rock mass, which will determine whether it collapses, is very complex. At the moment we don't know enough about it to be able to forecast its future behavior."
Outside of Alaska, on the west coast of Greenland, a landslide-produced tsunami towered 300 feet high, obliterating a fishing village in its path.
What the letter predicts for Barry Arm Fjord
Moving slowly at first...
Image source: whrc.org
"The effects would be especially severe near where the landslide enters the water at the head of Barry Arm. Additionally, areas of shallow water, or low-lying land near the shore, would be in danger even further from the source. A minor failure may not produce significant impacts beyond the inner parts of the fiord, while a complete failure could be destructive throughout Barry Arm, Harriman Fiord, and parts of Port Wells. Our initial results show complex impacts further from the landslide than Barry Arm, with over 30 foot waves in some distant bays, including Whittier."
The discovery of the impeding landslide began with an observation by the sister of geologist Hig Higman of Ground Truth, an organization in Seldovia, Alaska. Artist Valisa Higman was vacationing in the area and sent her brother some photos of worrying fractures she noticed in the slope, taken while she was on a boat cruising the fjord.
Higman confirmed his sister's hunch via available satellite imagery and, digging deeper, found that between 2009 and 2015 the slope had moved 600 feet downhill, leaving a prominent scar.
Ohio State's Chunli Dai unearthed a connection between the movement and the receding of the Barry Glacier. Comparison of the Barry Arm slope with other similar areas, combined with computer modeling of the possible resulting tsunamis, led to the publication of the group's letter.
While the full group of signatories from 14 organizations and institutions has only been working on the situation for a month, the implications were immediately clear. The signers include experts from Ohio State University, the University of Southern California, and the Anchorage and Fairbanks campuses of the University of Alaska.
Once informed of the open letter's contents, the Alaska's Department of Natural Resources immediately released a warning that "an increasingly likely landslide could generate a wave with devastating effects on fishermen and recreationalists."
How do you prepare for something like this?
Image source: whrc.org
The obvious question is what can be done to prepare for the landslide and tsunami? For one thing, there's more to understand about the upcoming event, and the researchers lay out their plan in the letter:
"To inform and refine hazard mitigation efforts, we would like to pursue several lines of investigation: Detect changes in the slope that might forewarn of a landslide, better understand what could trigger a landslide, and refine tsunami model projections. By mapping the landslide and nearby terrain, both above and below sea level, we can more accurately determine the basic physical dimensions of the landslide. This can be paired with GPS and seismic measurements made over time to see how the slope responds to changes in the glacier and to events like rainstorms and earthquakes. Field and satellite data can support near-real time hazard monitoring, while computer models of landslide and tsunami scenarios can help identify specific places that are most at risk."
In the letter, the authors reached out to those living in and visiting the area, asking, "What specific questions are most important to you?" and "What could be done to reduce the danger to people who want to visit or work in Barry Arm?" They also invited locals to let them know about any changes, including even small rock-falls and landslides.
What makes some people more likely to shiver than others?
Some people just aren't bothered by the cold, no matter how low the temperature dips. And the reason for this may be in a person's genes.
Eating veggies is good for you. Now we can stop debating how much we should eat.
- A massive new study confirms that five servings of fruit and veggies a day can lower the risk of death.
- The maximum benefit is found at two servings of fruit and three of veggies—anything more offers no extra benefit according to the researchers.
- Not all fruits and veggies are equal. Leafy greens are better for you than starchy corn and potatoes.