With Hong Kong in the throes of a serious wave of Covid-19 Omicron variant infections, Drs David Christopher Lung, Siddharth Sridhar and Yuen Kwok-yung of the Faculty of Medicine of The University of Hong Kong offer a sobering outlook for how the city can manage through the crisis, reopen and cope with possible future waves of the coronavirus.
Seniors struggle – shopping for necessities, Hong Kong, March 10, 2022: About 4,000 elderly, mainly unvaccinated rest-home residents, have died during the Omicron wave (Credit: HUI YT / Shutterstock.com)
Since the end of 2021, many regions around the world have experienced large waves of Covid-19 Omicron variant infections. Hong Kong has fared exceptionally badly in terms of death rate – the worst in the world over the pandemic – and the impact on society and healthcare. The unexpectedly high transmissibility of Omicron has effectively overwhelmed contact tracing and isolation efforts and quarantine capacity. The number of cases due to the BA.2 subvariant doubled every 1.28 days in the late-January 2022 outbreak in Yat Kwai House apartment block of Kwai Chung Estate. The large number of mutations in the spike protein of Omicron render vaccines much less likely to protect against infection, although protection against severe disease remains remarkably robust after three doses. Omicron is a game changer and could justifiably be regarded as a pandemic agent separate from the variants that came before it.
The central reason for the exceptionally bad situation in Hong Kong is due to the extremely low vaccination rate among the elderly despite nine months of availability of safe and effective vaccines. Many seniors with chronic medical conditions reside in homes for the aged that quickly became outbreak centers. A large influx of cases effectively caused the collapse of public medical services. Moreover, Hong Kong did not prepare well enough in terms of the surge capacity of outpatient and inpatient services despite knowing what had happened in Singapore and other places. About 4,000 elderly, mainly those affected by the outbreaks in rest homes, have died as of mid-March during the ongoing fifth wave of Covid-19 infections – and the death count has yet to peak.
Official estimates indicate that over 700,000 Hong Kong people (out of a total population of 7.4 million) have contracted Covid-19, although the real number is likely much higher, given that testing capacity has been exhausted. Extrapolating from the daily antigen/RT-PCR testing data of Hospital Authority staff which represents the working age group of 25 to 60, more than 19 percent of the population – at least 1.42 million – should be infected. The number could be as much as 3.6 million when estimated from mathematical modelling.
Although it is certain that Omicron is generally milder than the preceding Delta variant, markedly higher transmissibility means an equivalent burden of severe disease in an under-vaccinated elderly population. For healthy individuals fully vaccinated by the prototype 2019 virus, infection by the Omicron variant is often viewed as a good booster dose which may consolidate the antibodies or immunity against different variants. Still, getting infected is not good for anyone, including those at low risk of serious illness.
Infected elderly have flooded Hong Kong emergency rooms and hospital wards. This inevitably affects the standard of emergency and elective service for non-Covid-19 patients when entire wards and healthcare worker teams are barely coping with coronavirus cases. The few fatal cases in previously healthy and unvaccinated young children have understandably triggered a panic among parents and the general public.
Every wave eventually peaks. The plateau of the daily number of cases since March 4 reflects the impact of social distancing measures and a temporary herd-immunity effect due to the sheer number of cases. We still expect, however, to see hundreds of thousands of new infections as the wave recedes. The rest of March will be extremely difficult for Hong Kong. The need for the moment is mitigation of the epidemic.
While the government is trying its best to stop the outbreaks in elderly homes, improve outpatient service to prevent onset of severe disease in milder cases, improve inpatient service to reduce the mortality of those severe enough to be hospital inpatients, and accelerate the vaccination of seniors at elderly homes and in the community, it is also important to give hope to the public by giving them a concrete roadmap for going back to a more normal life.
We should continue to wear double masks and maintain sensible science-based non-pharmaceutical public health interventions until every eligible individual is vaccinated at least twice by the Pfizer-BioNTech (Comirnaty) or three times by the Sinovac-CoronaVac vaccines. This may happen by July if everybody is willing to come forward and more vaccination centers are opened. The supply of antivirals for treating early Covid-19 (Paxlovid and Molnupiravir) must be stabilized by then.
At the moment, it does not make sense for mildly infected persons to be transferred to community isolation facilities unless they face genuine difficulties in isolating at home. Trying to isolate every case at this time is an unnecessary nuisance to patients, their families and overworked civil servants except when the home condition is not suitable for isolation or quarantine. The pressing need of the moment is to improve infection outcomes in unvaccinated elderly, young children and chronically ill patients, especially when their household members are found to be infected. This reverse isolation of the susceptible population allows them to be serially tested, monitored and treated early to prevent complications.
We should allow close contacts with negative rapid antigen tests to go back to work, but they should wear double masks all the time when they leave their home. They should have daily antigen testing and isolate once the antigen test becomes positive. This policy is especially important for essential workers in the healthcare, ambulance and transportation service.
We should resume international flights between Hong Kong and the rest of the world. Any imported Covid-19 would only be a drop in the ocean of the transmissions that we are seeing locally. Pragmatic home quarantine for seven to 10 days is sufficient and they can come out if two sequential antigen tests are negative. We must not waste quarantine hotels while the community is already full of cases.
When the vaccination rate is high enough – over 95 percent, as achieved by the United Arab Emirates (UAE) – by summer when the temperature is higher and the environmental survival of the virus is poorer, we can gradually relax our social distancing measures while making the vaccine pass (implemented in February) mandatory for anyone going into public transports, schools, eateries, registered premises, government facilities and shopping malls.
The University of Hong Kong opened a community vaccination center
on campus on February 23, 2022 (Credit: HKU UVision)
The purpose of the vaccine pass is to protect unvaccinated individuals rather than punish them because these unvaccinated persons might potentially die from virus exposure. This would markedly reduce disease burden on our medical service because the infection of just 5 percent unvaccinated out of the 1.37 million elderly population could mean 68,500 patients reporting to hospital within one to two months during another wave. Assuming that anywhere from 20 percent to all of them would require admission within a six-week period, each of the18 major hospitals with emergency rooms would have to shoulder a mean of 13 to 65 elderly admissions a day, which looks manageable.
By that time, when a 95 percent vaccination rate is achieved, our surge capacity for isolation, quarantine, inpatient and outpatient services should be ready for this post-vaccination “sixth wave”. This wave could be started by a superspreading event from a residual cryptic transmission chain from the fifth wave due to the Omicron virus or from another incoming traveler or a new post-Omicron variant. As long as this post-vaccination wave is due to an Omicron-like variant, there should be little panic or disruption when a more normal life can go on, which has been the case in Singapore.
Whether we should still do compulsory universal testing would depend on whether all supporting logistics are ready and whether our contact tracing ability to mop up any residual cases is foolproof. Hong Kong had been very successful in achieving nine months of zero Covid-19 in 2021 with border control, universal single-masking, testing of symptomatic cases, contact tracing, isolation and quarantine against the third and fourth wave due to the Alpha and Delta variants. This past strategy, however, has obviously failed to control Omicron.
Compulsory universal testing has been very successful in the mainland in achieving zero because of their closed-loop management of isolation and quarantine premises. More important have been their very rapid and comprehensive contact-tracing capability by mobile phone, CCTV monitoring with facial recognition, artificial intelligence and epidemic management committee in every street and housing estate.
If Hong Kong is not ready with the supporting logistics for universal testing and the capacity for rapid multilayer contact tracing, the fifth wave will lead to a relapse or a sixth wave will readily come when another variant appears. If such an expensive exercise is soon followed by another spike in case counts or another wave, this would trigger an extreme degree of disappointment among our pandemic-fatigued citizens which would be the most undesirable outcome after two years of subnormal living.
It is unrealistic to believe that this Covid-19 virus will go away spontaneously as the 2003 SARS virus did. Like other common-cold coronaviruses, the degree of immunity from Covid-19 recovery or after vaccination cannot protect our upper airway from infection especially when the immunity wanes in six to 12 months. We have to ask ourselves how many rounds of compulsory universal testing can we tolerate since we would relax social distancing and border-control measures when our vaccination rate goes above 95 percent.
Our community should offer deep condolences to the family members of the 4,000 deceased elderly who were mostly unvaccinated or just partially vaccinated. Considering that this wave has been the most serious public health crisis in Hong Kong’s modern history, a monument to the fallen should be erected after we exit the pandemic. Besides commemorating the tragic loss of human life, this would become a sober reminder of the danger of ignoring overwhelming scientific evidence supporting the use of life-saving vaccines.
Allowing the lapse of a golden window of opportunity over nine months in 2021 to get enough people vaccinated, especially the elderly, against complications and death from Covid-19 was a tragic mistake. When all the serious scientific journal publications show that the benefit of the vaccines markedly outweigh their minimal side effects, there is little doubt that many, if not most, of the deceased could have been saved. This is the collective burden that Hong Kong will have to bear as it navigates itself through the pandemic era.
Cheng, Lilian. (March 11, 2022) “’Unprepared and disorganised’: where did Hong Kong government go wrong its fight against fifth wave of coronavirus?”, South China Morning Post, Hong Kong.
Kan, Deborah. (November 25, 2021) “Why I Left Hong Kong: The Hidden Crisis of Covid-19”, AsiaGlobal Online, Asia Global Institute, The University of Hong Kong.
Yuen, Kwok-yung; Lung, David Christopher; and Fan, Ivan Fan-ngai. (January 6, 2022) “The Road to Reopening Hong Kong”, AsiaGlobal Online, Asia Global Institute, The University of Hong Kong.
David Christopher Lung
The University of Hong Kong
The University of Hong Kong
The University of Hong Kong