Public use of surgical masks, airport screenings, and so-called "involuntary quarantine” — forced isolation — are all being used to try to contain the coronavirus outbreak, writes MedicalBrief. But do they work or just give us a false sense of security?
The decision to quarantine at least 50m people in cities in China – including Wuhan, a regional capital that is larger than London – has triggered both praise and condemnation across the globe, reports The Daily Telegraph. Some experts argue that restricting travel is the only real way to stop a virus spreading further – especially considering the country recently celebrated Chinese New Year. The government estimate that this usually involves three billion trips across the country and region as people travel to meet friends and family. But other experts say that the draconian intervention – which is one of the largest quarantines in global history – will only spread panic and drive cases underground.
“Involuntary quarantines have a questionable track record and can often be counterproductive,” said Jeremy Konyndyk, a senior fellow at the Centre for Global Development and former Obama era director of USAID Office of US Foreign Disaster Assistance is quoted in the report as saying.
People wearing face masks have become a defining image of large disease outbreaks, and this one is no different, with cities in Asia already reporting shortages as masks fly off the shelves. But in reality, the report says, the thin material masks do little to stop a respiratory virus spreading. “The face masks that we see people wearing are surgical face masks,” said Dr Mark Parrish, regional medical director of the medical and travel security firm International SOS. “As you breathe in and out, you're breathing air from outside the face mask. So, it will stop a little bit but not hugely.”
Jonathan Ball, professor of molecular virology at the University of Nottingham, added that face masks were proven to be effective in hospitals. “There are reports in literature that face masks in a hospital setting can protect health care workers. But there, they are being used for short periods by trained professions, changed frequently and properly disposed of. Those staff are also adopting good personal hygiene.
“But in the general population it may even be the case that they’re not helpful at all,” he added. “If you don’t change them regularly enough, they could potentially start to trap viruses and eventually they can move through that mask into your respiratory tract.”
The report says numerous countries across the globe, including the UK, have introduced screening at airports, but the limit here is that only those who are already ill will be picked up. So health experts say the most effective way to control the spread of viruses is an alert health system and high standards of infection control.
Professor David Heymann, infectious disease expert at the London School of Hygiene and Tropical Medicine, said that perhaps the most valuable element of airport screening is telling passengers about the signs and symptoms of a disease and what they should do if they’re worried.
“Educating the public is key,” he told. “The measures we have to adopt are diagnosing and isolating cases as quickly as possible so they are unable to transmit onwards,” added Professor Neil Ferguson, a disease outbreak scientist at Imperial College London.
The hope is that wearing masks in high-risk areas will at least slow the spread of the disease, but just how helpful they are is moot. The Guardian reports that Raina MacIntyre, a professor of global biosecurity at the University of New South Wales, has been reviewing the literature on protocol for dealing with infectious diseases and finds it wanting.
Surgical masks are only expected to help protect against larger droplets, and are designed not to protect the wearers themselves from germs but the open wounds of patients on operating tables. But even studies looking at whether they sufficiently protect patients in this way have not been able to prove their efficacy. Furthermore, says MacIntyre, “surgical masks are not regulated. Anyone can sell anything and call it a surgical mask. The filtration level of the material is not regulated.
In 2008 Catherine Makison Booth, a microbiologist at the UK’s Health and Safety Laboratory, set out to discover to what extent surgical masks could protect wearers.
She hooked up one of her dummies to a resuscitation machine, “so it breathed”, she says. She then sealed it in a cabinet and sprayed tiny airborne droplets – a simulated sneeze – containing influenza at it while it wore a series of protective masks.
Different designs of surgical mask were tested, including the standard strip of fabric, a duck-bill-shaped one and a 3D moulded one. “They conferred a low level of protection to the wearer,” she says, diplomatically. The virus was found inside all the masks, but they had provided something like a six-fold decrease in the amount of virus exposure.
Wearing a substandard mask may at least deter wearers from self-contaminating by putting their hands to their noses or mouths, but we can self-contaminate by touching our eyes, too. “We know that in the markets in Wuhan,” says MacIntyre, “they found coronavirus all over the surfaces, so someone walking through could touch it and contaminate themselves.”
However, truly protecting yourself isn’t as simple as buying any old FFP. There is a dizzying array on offer, with confusingly similar names, and in the west they are more likely to be marketed for pollution than disease. “N95” types are heavily promoted online.
Makison Booth says this is the US equivalent of the UK’s second-most-effective model, imaginatively called the FFP2. However, she says, “we recommend the use of an FFP3 (the highest protection available) because it will filter out more particles”. The US versions are tested only for dry particulates, she says, but the UK FFPs are tested against liquid in aerosols, too. Before you buy any mask, make sure it has a CE certification mark, which indicates conformity with EU health, safety and environmental protection standards.
There is little point in wearing one without testing that it fits properly, and most manufacturers sell fit-testing kits. “Areas such as the bridge of your nose to your cheek and under the chin are often places where air will leak through, rather than going through the filter material,” says Makison Booth. A standard test involves wearing the respirator, placing a plastic hood around your head and spraying saccharin solution inside it. “If you’ve got a leak, then you will be able to taste the sweetness,” she says.
Makison Booth also tested disposable filtering facepiece (FFP) respirators. They are designed to filter tiny particulates, and are recommended in the UK for professionals working under possible exposure to airborne diseases. These provided 100 times more protection than going barefaced.
[link url="https://www.telegraph.co.uk/global-health/science-and-disease/coronavirus-do-face-masks-airport-screenings-work/"]Full report in The Daily Telegraph[/link]
[link url="https://www.theguardian.com/world/2020/jan/31/our-face-mask-future-do-they-really-help-beat-flu-coronavirus-and-pollution?CMP=Share_iOSApp_Other"]Full report in The Guardian[/link]
[link url="https://www.who.int/emergencies/diseases/novel-coronavirus-2019/advice-for-public"]WHO advice to the public on combatting coronavirus[/link]