Wuhan Coronavirus Looks Increasingly Like a Pandemic, Experts Say


The Wuhan coronavirus spreading from China is now more likely to grow to be a pandemic that circles the globe, in accordance with lots of the world’s main infectious illness consultants.

The prospect is daunting. A pandemic — an ongoing epidemic on two or extra continents — could nicely have world penalties, regardless of the extraordinary journey restrictions and quarantines now imposed by China and different nations, together with the United States.

Scientists don’t but know the way deadly the brand new coronavirus is, nevertheless, so there may be uncertainty about how a lot harm a pandemic would possibly trigger. But there may be rising consensus that the pathogen is instantly transmitted between people.

The Wuhan coronavirus is spreading extra like influenza, which is very transmissible, than like its slow-moving viral cousins, SARS and MERS, scientists have discovered.

“It’s very, very transmissible, and it almost certainly is going to be a pandemic,” stated Dr. Anthony S. Fauci, director of the National Institute of Allergy and Infectious Disease.

“But will it be catastrophic? I don’t know.”

In the final three weeks, the variety of lab-confirmed instances has soared from about 50 in China to greater than 17,000 in at least 23 countries; there have been more than 360 deaths.

But various epidemiological models estimate that the real number of cases is 100,000 or even more. While that expansion is not as rapid as that of flu or measles, it is an enormous leap beyond what virologists saw when SARS and MERS emerged.

When SARS was vanquished in July 2003 after spreading for nine months, only 8,098 cases had been confirmed. MERS has been circulating since 2012, but there have been only about 2,500 known cases.

The biggest uncertainty now, experts said, is how many people around the world will die. SARS killed about 10 percent of those who got it, and MERS now kills about one of three.

It is “increasingly unlikely that the virus can be contained,” said Dr. Thomas R. Frieden, a former director of the Centers for Disease Control and Prevention who now runs Resolve to Save Lives, a nonprofit devoted to fighting epidemics.

  • Updated Feb. 5, 2020

    • Where has the virus spread?
      You can track its movement with this map.
    • How is the United States being affected?
      There have been at least a dozen cases. American citizens and permanent residents who fly to the United States from China are now subject to a two-week quarantine.
    • What if I’m traveling?
      Several countries, including the United States, have discouraged travel to China, and several airlines have canceled flights. Many travelers have been left in limbo while looking to change or cancel bookings.
    • How do I keep myself and others safe?
      Washing your hands is the most important thing you can do.

“It is therefore likely that it will spread, as flu and other organisms do, but we still don’t know how far, wide or deadly it will be.”

In the early days of the 2009 flu pandemic, “they were talking about Armageddon in Mexico,” Dr. Fauci said. (That virus first emerged in pig-farming areas in Mexico’s Veracruz State.) “But it turned out to not be that severe.”

An accurate estimate of the virus’s lethality will not be possible until certain kinds of studies can be done: blood tests to see how many people have antibodies, household studies to learn how often it infects family members, and genetic sequencing to determine whether some strains are more dangerous than others.

Closing borders to highly infectious pathogens never succeeds completely, experts said, because all frontiers are somewhat porous. Nonetheless, closings and rigorous screening may slow the spread, which will buy time for the development of drug treatments and vaccines.

Other important unknowns include who is most at risk, whether coughing or contaminated surfaces are more likely to transmit the virus, how fast the virus can mutate and whether it will fade out when the weather warms.

But life in China has radically changed in the last two weeks. Streets are deserted, public events are canceled, and citizens are wearing masks and washing their hands, Dr. Lipkin said. All of that may have slowed down what lab testing indicated was exponential growth in the infection.

It’s unclear exactly how accurate tests done in overwhelmed Chinese laboratories are. On the one hand, Chinese state media have reported test kit shortages and processing bottlenecks, which could produce an undercount.

But Dr. Lipkin said he knew of one lab running 5,000 samples a day, which might produce some false-positive results, inflating the count. “You can’t possibly do quality control at that rate,” he said.

Anecdotal reports from China, and one published study from Germany, indicate that some people infected with the Wuhan coronavirus can pass it on before they show symptoms. That may make border-screening much harder, scientists said.

Epidemiological modeling released Friday by the European Center for Disease Prevention and Control estimated that 75 percent of infected people reaching Europe from China would still be in the incubation periods upon arrival, and therefore not detected by airport screening, which looks for fevers, coughs and breathing difficulties.

But if thermal cameras miss victims who are beyond incubation and actively infecting others, the real number of missed carriers may be higher than 75 percent.

Still, asymptomatic carriers “are not normally major drivers of epidemics,” Dr. Fauci said. Most people get ill from someone they know to be sick — a family member, a co-worker or a patient, for example.

The virus’s most vulnerable target is Africa, many experts said. More than 1 million expatriate Chinese work there, mostly on mining, drilling or engineering projects. Also, many Africans work and study in China and other countries where the virus has been found.

If anyone on the continent has the virus now, “I’m not sure the diagnostic systems are in place to detect it,” said Dr. Daniel Bausch, head of scientific programs for the American Society of Tropical Medicine and Hygiene, who is consulting with the W.H.O. on the outbreak.

South Africa and Senegal could probably diagnose it, he said. Nigeria and some other countries have asked the W.H.O. for the genetic materials and training they need to perform diagnostic tests, but that will take time.

It is possible that the Wuhan coronavirus will fade out as weather warms. Many viruses, like flu, measles and norovirus, thrive in cold, dry air. The SARS outbreak began in winter, and MERS transmission also peaks then, though that may be related to transmission in newborn camels.

Four mild coronaviruses cause about a quarter of the nation’s common colds, which also peak in winter.

That aspect of the process cannot be sped up, because dangerous side effects may take time to appear and because human immune systems need time to produce the antibodies that show whether a vaccine is working.

Whether or not what is being tried in China will be acceptable elsewhere will depend on how rigorously Chinese doctors run their clinical trials.

“In God we trust,” Dr. Schaffner said. “All others must provide data.”



Source link Nytimes.com

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