Since the new avian flu strain H7N9 began appearing in China earlier this year, it's infected over 100 people, killed 22, spread to five provinces plus Beijing and Shanghai and, as of Wednesday, is confirmed to have spread abroad to Taiwan.
How worried should you be about this? How serious is the H7N9 outbreak? The simplest and most honest answer is that we don't know what's going to happen next, either with the virus, which may or may not mutate and become more transmittable, or with Chinese and international health-care authorities responsible for tamping it down. But there are some good signs, some bad signs and some very bad signs. Here are a few.
Three good signs
1. China is being unusually transparent so far. Ten years ago, as the deadly viral respiratory illness known as SARS first spread across China, the government did not respond well. It suppressed information about the outbreak, making it that much harder to contain and study the disease, ultimately costing lives. This time, though, Chinese authorities have been sharing information about the disease's spread, and state media appear to be freely reporting on new cases. Chinese officials seem to take the disease seriously and want to combat its rise, even if it means overcoming more secretive instincts. All health care for H7N9 is now free in China, for example, to help encourage people to report cases.
2. The number of cases has largely flatlined in the last week. After weeks of rising cases, the number seems to have stayed stable at around 110 over the last week. Big caveats here that there might be cases we don't know about, and the count could change at any moment.
3. Shanghai has found some success limiting new cases. A lot of the cases started around Shanghai, but the city was able to reduce the number of new infections after it closed poultry markets, according to Laurie Garrett, a senior fellow at the Council on Foreign Relations covering health-care policy. The Wall Street Journal found the same thing.
Three bad signs
1. It's spreading. With cases recently reported in Shandong province and now in Taiwan, the virus seems to be moving outward.
2. No verified human-to-human transmissions, but it's possible. Neither China nor the World Health Organization has documented human-to-human transmission, which would allow the virus to spread far more quickly and widely, but nor have they ruled it out. The Taiwanese case had no known exposure to poultry.
3. Tough to identify birds with the virus. World Health Organization officials say the virus is more difficult to detect in sick poultry than were previous strains because the birds do not show symptoms that are as clearly identifiable. This makes it tougher to keep sick birds off the market.
Three very bad signs
1. It's very deadly, with 18 percent mortality so far. For comparison, tuberculosis has a mortality rate of about 4 or 5 percent in China. Still, the avian flu virus that had its first outbreaks in China in 2006, known as H5N1, has a mortality rate of 60 percent and has killed hundreds of people on multiple continents. It's way too early to tell H7N9's mortality rate, given that many infected patients have not yet fully recovered, but it's so far killed about 18 percent of patients.
2. "This is definitely one of the most lethal influenza viruses that we have seen so far." That's according to Keiji Fukuda, the World Health Organization's assistant director general for health, security and the environment, who added, "This is an unusually dangerous virus for humans." Fukuda said the WHO is still struggling to understand the disease, but he certainly seems to be sounding the alarm.
3. More easily transmitted than the 2006 avian flu outbreak. That's also according to the WHO's Fukuda, who says this new strain is more easily contracted than the H5N1 virus.