Benjamin J. Cowling is chair professor of epidemiology at the University of Hong Kong Photo: RTHK
- It is inevitable Hong Kong will be hit with a fifth wave sooner or later
- Meanwhile with no local covid transmission at present, there shouldn’t be a need for everyone to be wearing masks
- Much of the world will emerge from the pandemic and return to normal in spring — but not Hong Kong
- Government’s zero covid policy is preventing HK getting back to normal and could be abandoned now that we have effective vaccines and effective treatments
- The travel bubble with the mainland may prove unsustainable, like the Singapore one
- 21 days quarantine is not justified; 14 days is enough based on scientific evidence
- The type of masks giving most protection in the community are the KF94 ones made in Korea
Benjamin J. Cowling is chair professor of epidemiology at the University of Hong Kong. The story below, based on an interview with him, could save your life.
BUZZ began by asking the professor whether covid and influenza could be lumped together as respiratory diseases that we all need to guard against in the same ways. Ben said there have been zero cases of influenza in HK this year. This is because of mask wearing, social distancing, closures and so on. Normally HK will have around a million flu infections each year and about 1000 deaths. He said flu “will be back”.
A wide spectrum of respiratory diseases cause coughs and colds and other symptoms. “You and me could have a completely different experience with the same viral infection” and will respond to disease in quite different ways. Covid-19 is by far the most serious respiratory disease on average, 10-20 times more serious than flu, but there are still many people who have covid and find it to be a very mild illness.
He looked back at our experience with covid. In March last year we got the second wave, starting with the “bar and band cluster”, then the third wave in July starting with a number of outbreaks, then came the fourth wave starting with the “ballroom dancing cluster”. Each of these waves lasted for months scaring the community. A fifth wave is inevitable sooner or later. “We can’t keep it out indefinitely. It is not possible to reduce risk to zero.” Covid will get into the community possibly through people who do not have to be quarantined, perhaps aircrew, diplomats or business VIPs, or through staff at the airport or quarantine hotels.
The outbreak could come from a gym, say, or a family party. “If the Government reacts very quickly and decisively the fifth wave could be very small.” But the Delta variant is a much bigger threat than earlier variants and it could be difficult to stop a fifth wave with this variant. Or we may face a new variant in the future that we haven’t heard of yet.
BUZZ asked if covid takes off in the community when will we be in most danger. Professor Ben said avoid the “three Cs” — crowded places, confined areas and close contact for prolonged periods. In an epidemic avoid poorly ventilated restaurants and nightclubs. The MTR, buses and minibuses could also be risky, although he noted the trains are well ventilated. If covid is rampant, he would avoid a long journey on a bus or minibus if possible.
On masks, Ben said surgical masks tend to be better than cloth masks and the best surgical mask of all is the Korean-made KF94. It seals to your face well and has good filtration as you breath in and out. N95 respirators should be left to health professionals because they work best when they are fitted perfectly, not something that can be done in the wider community and without fit testing they may be no better than surgical masks, as well as being uncomfortable to wear.
How can you catch the disease? “It is not established that covid can be spread on surfaces, such as door handles or railings, like colds or flu. The virus doesn’t survive well on surfaces. Its transmission is airborne in droplets or particles of different sizes. But it doesn’t spread far, so avoid confined spaces and prolonged contact. Nevertheless, it’s a good habit to frequently wash your hands and do it thoroughly”.
On vaccination, in HK you have two choices, BioNTech-Pfizer or Sinovac. Ben recommends the former, but says Sinovac is better than nothing.
The BUZZ interviewer commented that he has yet to get the BioNTech jab because of fear his shingles may be reactivated. Ben said that this could happen in only about one in 10,000 or 100,000 cases. Some people suffer a little fever after being jabbed and get some pain at the injection site. On “very rare” occasions, serious reactions can occur: stroke, heart attack, anaphylactic shock or immunological consequences. He emphasised this is “very rare”. When covid is prevalent, the benefits of vaccination far outweigh the risks.
The world is in a far better position now coping with covid than it was last year. We have good vaccines and effective treatments. New anti-viral drugs can stop a mild case turning serious. Unfortunately we don’t yet have good treatments for severe cases. “In some severe cases it’s your own body that puts you into intensive care. Covid disrupts your normally finely balanced immune system and puts it into overdrive, and you’re in trouble.”
To those who are hanging back delaying getting the jab, Ben pointed out that it takes around 2-3 weeks after the second dose before you have good protection. After you take BioNTech it will be two to three weeks before you get some protection, then you get a second dose and move to a high level of protection. On the other hand, Ben said, we have had six months without covid transmission in the community and we may go another six months with no covid or it may be back next week. Do you want to accept the risk should a fifth wave take off?.
On 21 days hotel quarantine, Ben said it is unnecessary, 14 is enough, with tests before, during and after. There have been cases of people catching covid in hotel quarantine. The question is when did they catch it. If it is in the second or third week they are out in the community soon potentially as spreaders. “This shouldn’t be happening. Hotels are not designed like hospitals. If we are continuing the zero covid strategy in the long term, the Government should build special on-arrival quarantine facilities like Penny’s Bay.”
The winter will be tough but by next spring much of the world will return to normal, but not HK because of the zero covid policy. In responding to the massive threat to public health from covid, governments have had three choices: 1) public health measures — masks, social distancing, lockdowns; 2) effective treatments; and 3) effective vaccines. It’s only in the second year of the pandemic that we have effective treatments and effective vaccines. The places that did best of all managed least covid and least disruption. HK has been a leader in the first 18 months of the pandemic. But now because we have effective vaccines and treatments, Europe and America are on their way back to normal. But HK is not planning to return to normal, because of the zero covid policy. Ben said most places that used it in the first 18 months of the pandemic are now transitioning away from this strategy and replacing it with reliance on effective vaccines and effective treatments that reduce the threat of covid to something more comparable to the threat of seasonal flu.
In the meantime, while we stick with the zero covid strategy, we should take advantage of the quiet periods. “In Hong Kong we have the opportunity to relax public health measures while we have zero cases at the moment. We could have no face masks, no quarantines, no social distancing, no restrictions in the community,” because we have had six months of no covid. But if and when covid comes back, we will need them again.
Biography
Professor Benjamin Cowling joined the School of Public Health (SPH) at HKU in 2004. Prior to moving to Hong Kong, he graduated with a PhD in medical statistics at the University of Warwick (UK) in 2003, and spent a year as a postdoc at Imperial College London (UK). Professor Cowling has been the Head of the Division of Epidemiology and Biostatistics since 2013. He is responsible for teaching the introductory module in epidemiology on the MPH curriculum, and is the chairman of the Departmental Research Postgraduate Committee. Prof Cowling is a co-director of the WHO Collaborating Centre for Infectious Disease Epidemiology and Control at HKU SPH.
Prof Cowling’s primary research focus is in infectious disease epidemiology. In recent years he has designed and implemented large field studies of influenza transmission in the community and the effectiveness and impact of control measures. His latest research has focused on the modes of respiratory virus transmission, influenza vaccination effectiveness, and immunity to infections at the individual and population level. He has strong links with China CDC, and the NIGMS-funded Harvard Center for Communicable Disease Dynamics.
Professor Cowling is a fellow of the Royal Statistical Society and a Fellow of the UK Faculty of Public Health. He is the Editor-in-Chief of Influenza and Other Respiratory Viruses, and an Associate Editor of Emerging Infectious Diseases.
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