Why Omicron Is So Deadly in Hong Kong
By Siddharth Sridhar
Dr. Sridhar is a virologist at the University of Hong Kong.
"HONG KONG — For most of the Covid pandemic, life in Hong Kong remained a simulacrum of normal. The city maintained one of the world’s strictest border control measures, requiring inbound travelers to undergo quarantine in hotels for up to three weeks. Small waves of cases were quickly stopped with exhaustive contact tracing, strict hospital-based isolation and supervised quarantine in designated facilities. Mask mandates were introduced but were hardly necessary; masks, for the most part, have been spontaneously adopted by the general public since early 2020. This frenetic city of 7.5 million never locked down.
But now Hong Kong is struggling in the face of Omicron. Once the variant found a way past the city’s border controls in January, its high infectiousness meant that widespread transmission was a given.
The situation in Hong Kong is revealing because the city had many advantages: deep pockets, a free mass-vaccination program and ample time to prepare for exigencies of local outbreaks. But when the most vulnerable segment of the population remains unvaccinated and scientific facts on vaccine effectiveness are ignored, nothing is enough.
Hong Kong has one of the highest population densities in the world, and living space is scarce. Packed housing may have contributed to entire families getting infected. This breakneck spread quickly overwhelmed contact-tracing efforts and isolation facilities. A modeling study estimates that 3.7 million people were infected locally in a matter of weeks.
Although Omicron caused sharp surges in cases across the globe, Hong Kong stands out grimly for its Covid-19 death rate. The city’s Covid death toll is among the highest recorded at any one time during the pandemic. Emergency rooms are overflowing, hospitals are overwhelmed, and nursing homes are facing devastating outbreaks. As a doctor who has worked in Hong Kong for more than a decade, I found this devastating to witness. How did one of the world’s richest cities end up here, more than two years into the pandemic?
The most important factor behind the gruesome death toll is low vaccination uptake among Hong Kong’s elderly population. Since early 2021, Hong Kong residents were offered a choice between two vaccines: an mRNA vaccine (Comirnaty, made by BioNTech and Fosun Pharma) and an inactivated vaccine (CoronaVac, made by the Chinese company Sinovac). Almost immediately after the campaign began, a steady drumbeat of vaccine misinformation began on social media. A small number of deaths that occurred within 14 days of vaccine administration (ruled unrelated to vaccines by investigations) were breathlessly brandished as evidence that the new vaccines were unsafe, especially for elderly people with medical conditions, who, ironically, needed them the most.
Moreover, because there’s been a zero-Covid policy, until this year, there had been very few cases in the community. This has likely contributed to further vaccine hesitancy, as Covid-19 was simply not perceived as a credible threat. The public vaccination campaign did not succeed in correcting this distorted risk perception, and incentives for the vaccinated came too late. A vaccine passport for restaurants and indoor activities was rolled out only in February 2022. As a result, vaccine uptake for people 70 and older at the beginning of this year was less than 50 percent. Most Hong Kongers did not contract this coronavirus previously, meaning that vaccinations were effectively the only way to build a wall of protection against severe Covid-19. All this made Hong Kong a ticking time bomb that is now exploding in slow motion.
The Hong Kong story isn’t about mRNA vaccines versus inactivated vaccines. Although three doses of the mRNA version are more effective against Omicron, both types confer some degree of protection against severe disease. Even if Hong Kong’s elderly had all chosen the inactivated vaccine, the situation would not be as bad as it is now. The numbers speak for themselves: About 90 percent of the deceased in Hong Kong’s fifth wave had not received two doses of a vaccine. For an unvaccinated person above the age of 80, the case fatality rate in Hong Kong is a whopping 12 percent. This shrinks to 3 percent for those who received two doses of any Covid-19 vaccine.
There were other contributing factors in this debacle. Hong Kong’s highly affordable publicly subsidized health care infrastructure has suffered chronic shortages of space and staffing for a long time, leaving hospitals vulnerable when demand surged. Omicron brutally exposed these cracks. A more transmissible virus afflicting a massively undervaccinated older population led to crowds of patients thronging emergency rooms. Temporary triage stations had to be erected outside hospitals, where people often had to wait long periods in cold weather for admission to inpatient facilities, which in turn were quickly overwhelmed. Many health care workers were required to isolate themselves because they got infected, exacerbating the problem.
We are now seeing a decentralization of care to nursing homes and designated community clinics. Oral antivirals are finally being made available for early Covid-19 treatment to vulnerable unvaccinated individuals in the community. Hong Kong is being forced by circumstances to abandon a futile containment strategy and try to mitigate the worst effects of the local epidemic. However, this is too late for the more than 4,000 people dead, many of whom were elderly people residing in nursing homes.
Hong Kong could have fared better against Omicron if vaccination rates had been much higher. The city’s experience gives the lie to the simplistic narrative that Omicron is mild. Its severity is highly contextual. And in Hong Kong’s context, Omicron brought about a perfect storm."
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