Chandrakant Lahariya | Lesson from China's surge: Don't drop guard on Covid

For nearly three years, China adopted a "Zero Covid" strategy, with some stringent measures and harsh restrictions. This was continued despite all the epidemiological evidence of its ineffectiveness and the abandoning of the "Zero Covid" strategy by other countries like Australia, New Zealand and Singapore. Then, with the highly transmissible Omicron, it became unequivocally clear that "Zero Covid" is not an effective strategy for Covid-19 response. China definitely continued the enforcement of the "Zero Covid" approach till a few weeks ago, when it was abandoned in haste after citizens' protests and civil unrest -- something that is almost unprecedented in China.

For nearly 35 months, a "Zero Covid" strategy essentially meant that with a reportedly low infection rate, of around 1.4 billion people in China, only a small proportion of the population developed immunity through natural infection. Second, though China has vaccinated a vast majority of the population; the efficacy of the Covid-19 vaccines used in China is the lowest amongst all approved Covid-19 vaccines, at around 52 per cent. Third, China had started Covid-19 vaccination nearly two years ago, and completed it at a fast pace. We know that the vaccine-induced immunity declines with time. Thus, even with the high vaccine coverage, the protected population in the best-case scenario was just half of the total eligible population, and in the worst-case scenario (given the decline in protective immunity over time), to even a smaller proportion. Fourth, the protection and immunity developed after natural infection lasts longer than vaccine-induced immunity. However, the population in China has only vaccine-induced immunity, that wanes off with time.

Therefore, in early December 2022, when China made a tectonic policy shift from its "Zero Covid" strategy, the country, arguably, may have had an estimated 850 million to 1,120 million susceptible people, most of whom hadn't been exposed to any SARS CoV2 variant.

With Omicron being the dominant variant of concern, that spreads fastest amongst all Covid-19 variants, the current surge in China is not something we should be surprised about. Rather, what's more surprising is that China didn't prepare a "Zero Covid" exit strategy in a nuanced and meticulous way. After all, in December 2022, the world has a far better understanding of how to respond and how to take care of those who get infections. There are vaccines which protect from moderate to severe diseases and there are Covid-19 drugs which work best in population groups such as in China: no past infection and no vaccination. With the sudden relaxation in Covid-19 curbs, specially when vulnerable population groups like the elderly remain unvaccinated, the surge in China is what an epidemiologist would call unavoidable. In fact, in the time ahead, as immunity wanes, similar though localised surges might be reported from other countries and sub-national settings. All countries should be prepared and should have mechanisms in place for responding to such eventualities.

The lack of official information from China and unverified videos of overburdened hospitals in the social media has given space for estimates and mathematical projections and fuelled misinformation. Yet, those who have worked in disease modelling know the Covid-19 situation has become far more complex and factoring in all these determinants and variables makes any mathematical models unstable and thus unreliable. Yet, a simplified model with multiple assumptions generates estimates with very wide confidence intervals, which may not be any better than the guesstimates. Clearly, the estimates on Covid hospitalisations and deaths in China should be read with, not just a pinch, but with a "handful of salt".

Yet, considering the world is in midst of a pandemic, a Covid-19 surge in any part of the world is a reason for every other country to take note. But it is not a reason to panic or worry. Three years into the pandemic, no two countries are comparable, because of the differences in the rate of natural infection, in the efficacy and coverage with vaccines, also due to whether vaccines were administered before or after natural infection in those settings and the time elapsed since the completed vaccination.

Unlike China, India has a high natural infection (after three waves), high adult vaccine coverage with high efficacy vaccines, and a hybrid immunity (far superior than any vaccine-induced immunity). The surge in China can't give rise to a fresh wave in India or any other country. The only unknown is whether it is the Omicron variant that is circulating in China or if it is a new variant. China doesn't have an impressive record on reporting about the SARS CoV2 infection and spread in the past. Therefore, countries need to be extra cautious and urgently need to step up genomic surveillance.

The surge in China is a reminder that the world cannot drop its guard against the virus. However, the response should not be knee-jerk. There is no need for flight bans or other travel restrictions. Essentially, just because cases are rising in China, it's not a reason to bring back the mask mandate either. One real ongoing challenge is tackling misinformation. It is possible that soon -- in India and elsewhere -- there will be talk and suggestions to implement preventive measures, such as bringing mask mandates back, consider moving to a hybrid mode of schools and other unscientific measures which gives governments a semblance of doing something. Any of these measures have no role as of now, in any setting outside China.

The surge in China has not changed anything in India and there is no need to change people-related approaches in the Covid-19 response in India. At an individual level, there is nothing to worry about for people. But all countries other than China, including India, need to urgently step up their genomic surveillance, sewage surveillance and monitor any early trend in clinical symptoms and outcome of infections. The government authorities must keep close watch on trends in China and other nations. The epidemic and pandemic response need nuanced, evidence-guided strategies derived from ongoing learning, and not a dogmatic response. "He who rides a tiger is afraid to dismount" is a famous saying. China's "Zero Covid" strategy was like riding a tiger. As China has dismounted, the policymakers there urgently need to bring granularity in response, adopt calibrated steps, remove restrictions and implement steps to protect the vulnerable. More important, it is a moral responsibility of the government in China to report Covid-19 specific data (cases, deaths and data for genomic surveillance) with the world and international bodies.