Omicron wreaks havoc among immunologically naïve populations

On Friday, March 4, 2022 a new chapter of the pandemic has started in New York City: wearing masks in schools, restaurants, bars and many other public places will no longer be required and customers can enter such locations without a proof-of-vaccination or a negative test result.

These relaxation measures have increased in frequency in other American states too, as well as many countries across the globe, as the highly-contagious Omicron variant is starting to subside, giving rise to hopes that the Coronavirus pandemic is entering its endemic phase.

However, while many scientists argue that Omicron is intrinsically less severe than other coronavirus variants such as Delta, affecting the upper respiratory tract rather than the lungs, others warn that it is far from being just a “simple cold” and that people should continue to be vigilant. For instance, an expert panel advising Japan’s health ministry announced on March 2 that the fatality rate from Omicron was 40 percent higher than that of seasonal flu.

Omicron’s virulence – especially in populations with low levels of previously acquired immunity from vaccination or prior infection – is nowhere more visible today than in Hong Kong. For much of the pandemic, Hong Kong was a model of success in the fight against the Coronavirus. Their “zero Covid” approach kept cases and deaths very low, and allowed daily activities to continue in a relatively normal way. 

However, once the Omicron wave started, Hong Kong has witnessed a terrifying spike in cases, hospitalization, and deaths. Today, bodies are piling up in hospital hallways because officials can’t move the dead fast enough.

Part of the reason for this gruesome situation – reminiscent of India’s near collapse under the Delta wave from the spring of 2021 – is Hong Kong’s low vaccination rates, particularly among the elderly. For instance, only about 30 percent of people over 80 are vaccinated. 

According to Karen Grepin, an associate professor at the School of Public Health at the University of Hong Kong, the “zero Covid” approach was so successful before that the citizens of Hong Kong have “started to believe that even the minuscule risk associated with vaccination was higher than the risk of Covid” and are now “paying for that complacency.” 

By contrast, other countries that followed a “zero Covid” policy but had a highly vaccinated population, such as Australia, New Zealand, or Singapore are faring much better during their (unavoidable) Omicron waves. This shows that, while Omicron may indeed be less pathogenic than other variants, it still poses a high risk for immunologically naïve populations, and highlights once more the importance of vaccination, particularly among vulnerable populations.  

—

By Andrei Ionescu, Earth.com Staff Writer