(Bloomberg Opinion) -- China’s zero-Covid policy initially provided a shield from viral infection and an example of disciplined pandemic management. It’s now become a trap from which Beijing is trying to escape without provoking a major health crisis. But being stuck on a home-grown solution is likely to lead to more problems, as Bloomberg Opinion’s Therese Raphael and Bloomberg Intelligence pharmaceutical analyst Sam Fazeli discuss here.
Therese Raphael: China’s recently tweaked strategy, known as “dynamic clearing,” shifts responsibility to local authorities to contain outbreaks. But it’s not a solution, as we’ve written before. And the situation in Hong Kong, where lockdowns and draconian social restrictions to contain infections has ruined quality of life for many, demonstrates the folly of zero Covid for trying to prevent infection or eliminate the virus.
Zero Covid, as we wrote recently, is a dead end for China. But Beijing worries that lifting restrictions would quickly lead to a huge spike in cases that will overwhelm the health-care system. That certainly seems to be the lesson from Hong Kong. How valid is that concern for China now?
Sam Fazeli: It’s a real concern, as Hong Kong shows. The omicron variant is better at evading the immune system even of those who have had three shots of a highly effective mRNA vaccine. So in China, with a lower level of vaccination among the elderly and less effective vaccines, the risk is very real. Even though the omicron variant does appear to cause less severe disease in Western countries, a lot of this is due to the background immunity that has been generated by vaccines, infections or both. China also has far fewer intensive care beds than other countries (an estimated 4.37 beds per 100,000 people compared with 34.7 in the U.S. and 29.2 in Germany).
TR: Some 87% of the Chinese population has been vaccinated and about one-third has received a booster shot, though vaccination levels aren’t evenly spread around the country. Problem is, the inactivated-virus vaccines from Sinovac and Sinopharm, which use a killed virus to provoke an immune reaction, lose effectiveness more quickly than the mRNA vaccines. What kind of gap in vaccine effectiveness are we seeing?
SF: There are few studies that directly compare mRNA vaccine effectiveness with killed-virus vaccines. The reason is that the different vaccines have rarely been used in the same population, except in some Latin and Central American countries.
A recent study in Nature showed the scale of the issue. A booster dose of Pfizer-BioNTech's vaccine elicited neutralizing antibody levels above a threshold deemed to halve the risk of an omicron infection in 88% of individuals (22 of 25) who previously received two doses of the vaccine and 80% of individuals (24 of 30) who previously received CoronaVac, which is the vaccine from Sinovac. But, only 3% of those vaccinated with three doses of CoronaVac met this threshold.
Another study showed a very strong rise in neutralizing antibody levels after CoronaVac against omicron in those previously infected, though this was still lower than with all other vaccines. The problem is that because of the zero-Covid policy, there are very low levels of prior infection in China.
TR: Shanghai-based Fosun Pharmaceuticals was licensed to manufacture and distribute BioNTech’s vaccine in China. What happened there?
SF: The Fosun deal does not seem to have made much progress, though clinical data has been submitted to local regulatory authorities. The slow progress may be because China wants to have its own vaccines used across its population. But in its most recent comments, BioNTech's management appeared more positive about the potential for approval. Also, the recent approval of Pfizer's Paxlovid may signal a policy change in China.
TR: Is China getting anywhere in developing its own home-grown mRNA vaccines? Does it make any sense to wait for that?
SF: Well there is one that has made some progress. Walvax's ARCoV induced neutralizing antibody levels twice that of convalescent plasma in patients who recovered from Covid-19. But at a higher dose of the vaccine, neutralizing antibody levels were lower, suggesting real-world challenges in identifying the right dose required to achieve optimal efficacy.
But the real issue is that the vaccine only targets the receptor binding domain (RBD) of the virus's spike protein. This is a version of the mRNA vaccine which Pfizer-BioNTech abandoned due to high side effects, which Walvax has also seen. Additionally, this kind of vaccine will be much more prone to loss of effectiveness in the face of new variants as a majority of mutations happen in that region of the spike.
TR: If China did approve Western vaccines for distribution, what impact would that have on global supplies and especially distribution to developing countries that still have low levels of vaccination?
SF: It should have little impact as the initial volume is only 100 million doses manufactured in Germany for Fosun to distribute in China. There is also a chance that lackluster interest in fourth shots in Western countries may lead to a lot of vaccine doses looking for a home. But the data we referred to above in terms of effect of a third dose of Pfizer-BioNTech's vaccine after two shots of CoronaVac, suggests that this would be China's best hope of getting out of the zero-Covid trap with the least number of hospitalizations and deaths. The challenge will be getting its elderly population, among whom vaccination levels are relatively low, to take yet another shot.
TR: What other pharmacological defenses does China have and are they enough to allow a loosening of the restrictions?
SF: China very recently approved Pfizer's Paxlovid, which has a very high level of efficacy against hospitalizations. The problem is that the drug has to be used in the first five days after an infection is detected or symptoms start, so requires a timely test. That means China needs to change its policies quite substantially as the drug only really works against an active infection and is still being tested as a prophylactic, with data due later in the year. So there will be significant logistical challenges if China was to only rely on Paxlovid.
TR: Finally, data from Israel have confirmed suspicions that a fourth shot doesn’t add a lot. How robust is that data and would that factor into Chinese calculations or would a fourth shot be more likely there given the relative ineffectiveness of the Chinese vaccines?
SF: The Israeli data is very early stage and we need more time, but the vaccine efficacy of a fourth dose against an omicron infection was low. In fact it was below the 50% which has been long viewed as a minimum for regulatory approval. But in China, a fourth shot of an mRNA vaccine after three shots of a killed virus vaccine may actually provide a very significant benefit, whether its the delta or omicron variant which is in circulation.
More From Bloomberg Opinion:
- Americans Are Going Everywhere Except Back to Work: Mark Ein
- Hong Kong Expats, Where’s Your Next Destination?: Anjani Trivedi
- Survival Tips for Hong Kong’s 21-Day Covid Quarantine: Shuli Ren
This column does not necessarily reflect the opinion of the editorial board or Bloomberg LP and its owners.
Therese Raphael is a columnist for Bloomberg Opinion. She was editorial page editor of the Wall Street Journal Europe.
Sam Fazeli is senior pharmaceuticals analyst for Bloomberg Intelligence and director of research for EMEA.
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