But since you're already here, I'll explain some of the important differences below. First, though, a quick look at the flu (influenza). In the US, there are between 9 and 45 million flu cases each year. They cause about 10-15 million doctor office visits, several hundred thousand hospitalizations, and about 20,000 to 40,000 death in a typical year.
If the new coronavirus would indeed be similar to the influenza virus, it would cause tens of millions of additional sicknesses per year, with tens of thousands of additional deaths, in the US. I leave it up to you whether you see that as something to worry about, or as "no big deal".
But let me outline a few ways in which the new corona virus (SARS-CoV-2) and the disease it causes differ from the flu virus and influenza:
- The flu has been around for 2000 years, but the corona virus only for 3 months. Most adults have had the flu at least once, which leads to at least some immunity. Any residual immunity will make a flu infection less severe; immunity from a relatively recent infection or vaccination with a similar flu virus will prevent the flu. There are also corona viruses that are common and cause colds, but there are so different from SARS-CoV-2 that they are very unlikely to provide immunity.
- We have vaccines for the flu, but will not have vaccines for the corona virus for at least a year. In the US, about half of the population gets a flu shot in any given year. In most years, the flu shots work well against the common flu viruses, and either prevent getting sick, or reduce the severeness of the disease. In years where the virus that goes around is too different from the virus in the vaccine, the number of flu cases goes up a lot; the 2017-2018 season with 45 million cases is an example. Without vaccination, the annual flu numbers would be at least this high in most years.
- The new corona virus is significantly more deadly than the influenza virus. The typical death rate for the flu in the US is about 0.1-0.15% (you can check the numbers yourself by looking at the table on the CDC website). The exact death rate for the corona virus differs somewhat depending on medical care and other factors, but it is currently around 2% for many countries. If additional problems like lack of intensive care beds occur, the rate can be significantly higher. In China, the current (March 10, 2020) number is 3.88% (80,761 cases and 3,136 deaths). Even with proper preparation and medical care, it is likely that the death rate will be at least 5-10 times higher than for the flu in most countries, including the US.
It is very important to understand these differences, both on a personal level and for larger-scale political decisions. As an overall healthy person, I'm not too worried about the flu, although I certainly try to avoid getting it (and sometimes get flu shots). But the chances that I'd die from getting the flu are just about zero. When it comes to a new disease where the change of dying from it are closer to 1 in 100, things are very different!
Similar thinking should apply on the society level, for example when it comes to the question of whether you should go to work if you might be infected. It has been shown that anyone infected with the corona virus is most likely to pass the disease on to others right at the onset of the first symptoms (and possibly even before). Going to work "because it's just like a cold" may work for you, but you are very likely to infect others, who go on infection others, and so on - making it just a question of time until someone in the infection "chain" that you caused has the severe form of the disease, or even dies.
It is interesting to look at differences between countries in this respect. In most European countries, all workers get paid sick leave - all they need is a doctor's note. But going to a crowded doctor's office to get such a note is a "great" way to spread the infection! Therefore, Germany has instituted a policy where everyone can get a week of sick days by just calling the doctor's office, and other European countries are likely to have or create similar policies.
In contrast, only a few states in the US have paid sick leave legislation; most employees either do not have paid sick leave, or paid sick leave is subtracted from vacation days (which are significantly less than in Europe). For many workers, especially hourly workers, not going to work when sick can cause significant economic problems from lost paychecks, or even lost jobs. As a result, "Nearly seven in ten workers (68 percent) report they have gone to work with the stomach flu or other contagious disease.", creating the problem of "Presenteeism". In the context of the corona virus, this would make containing the epidemic much harder.
The effect of going to work while sick can be seen when comparing the flu rate between the US and Germany. For the 2017-2018 season, these are the reported numbers (from the CDC and Statista) :
| USA | Germany | |
|---|---|---|
| Cases | 45,000,000 | 165,489 |
| Inhabitants | 327 million | 82 million |
| Cases per thousand | 138 | 2 |
| Deaths | 61,000 | 358 |
| Deaths per million | 186 | 4.36 |
After taking into account the differences in population size, the number of flu cases and deaths is more than 40-fold lower in Germany. A significant part of this difference is likely to be due to differences in how often sick people go to work, and thereby continue to spread the infection.
This post was originally posted on 3/10/2020 at boardsurfr.blogspot.com/2020/03/corona-virus-versus-influenza.html
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