[custom_adv] Wearing a face mask is certainly not an iron-clad guarantee that you won’t get sick – viruses can also transmit through the eyes and tiny viral particles, known as aerosols, can penetrate masks. [custom_adv] However, masks are effective at capturing droplets, which is a main transmission route of coronavirus, and some studies have estimated a roughly fivefold protection versus no barrier alone (although others have found lower levels of effectiveness). [custom_adv] If you are likely to be in close contact with someone infected, a mask cuts the chance of the disease being passed on. If you’re showing symptoms of coronavirus, or have been diagnosed, wearing a mask can also protect others. [custom_adv] So masks are crucial for health and social care workers looking after patients and are also recommended for family members who need to care for someone who is ill – ideally both the patient and carer should have a mask. [custom_adv] However, masks will probably make little difference if you’re just walking around town or taking a bus so there is no need to bulk-buy a huge supply. All viruses accumulate mutations over time and the virus that causes Covid-19 is no different. [custom_adv] How widespread different strains of a virus become depends on natural selection – the versions that can propagate quickest and replicate effectively in the body will be the most “successful”. [custom_adv] This doesn’t necessarily mean most dangerous for people though, as viruses that kill people rapidly or make them so sick that they are incapacitated may be less likely to be transmitted. [custom_adv] Genetic analysis by Chinese scientists of 103 samples of the virus, taken from patients in Wuhan and other cities, suggests that early on two main strains emerged, designated L and S. [custom_adv] Although the L strain appeared to be more prevalent than the S strain (about 70% of the samples belonged to the former), the S branch of the virus was found to be the ancestral version. [custom_adv] Many individuals who get coronavirus will experience nothing worse than seasonal flu symptoms, but the overall profile of the disease, including its mortality rate, looks more serious. At the start of an outbreak the apparent mortality rate can be an overestimate if a lot of mild cases are being missed. [custom_adv] But this week, a WHO expert suggested that this has not been the case with Covid-19. Bruce Aylward, who led an international mission to China to learn about the virus and the country’s response, said the evidence did not suggest that we were only seeing the tip of the iceberg. [custom_adv] If borne out by further testing, this could mean that current estimates of a roughly 1% fatality rate are accurate. This would make Covid-19 about 10 times more deadly than seasonal flu, which is estimated to kill between 290,000 and 650,000 people a year globally. [custom_adv] As the new coronavirus COVID-19 spreads in the U.S., people who are well want to stay that way. But since no vaccines are currently available, the strongest weapons Americans have are basic preventive measures like hand-washing and sanitizing surfaces, according to the Centers for Disease Control and Prevention (CDC). [custom_adv] The simplicity of those recommendations is likely unsettling to people anxious to do more to protect themselves, so it’s no surprise that face masks are in short supply—despite the CDC specifically not recommending them for healthy people trying to protect against COVID-19. [custom_adv] “It seems kind of intuitively obvious that if you put something—whether it’s a scarf or a mask—in front of your nose and mouth, that will filter out some of these viruses that are floating around out there,” says Dr. William Schaffner, professor of medicine in the division of infectious diseases at Vanderbilt University.