An analysis of blood samples from 450 Hungarians taken at least two weeks after the second Sinopharm dose revealed that 90% of them had developed protective antibodies. However, the percentage of people over 80 having no protective antibodies decreased with age.
The study by two Hungarian researchers was posted online this week but not yet reviewed by other scientists. Three experts outside said that they were satisfied with the method used to study the vaccine from Sinopharm's Beijing Institute of Biological Products.
Jin Dong-yan, a Hong Kong University virologist, said, "This is very, very worrying because these people who are high-risk have a poor antibody reaction."
Although antibody levels do not directly measure how protected someone is from COVID-19 they are becoming more reliable. Experts cautioned that incorrect test kits may have affected the accuracy of measurements.
The study's results are still valuable and represent the first scientific attempt to analyze the effects of Sinopharm in elderly patients, according to Wang Chenguang. Wang Chenguang is an ex-president at Peking Union Medical College, and an immunology expert.
The China National Health Commission refused to comment on the study and said it would only respond to research by major research institutions or governments.
This is not the first time questions have been raised about the efficacy of the vaccine, which was given a greenlight by the World Health Organization in May and is being used in more than 50 countries, many of which seized upon it when other vaccines were tough to come by.
A WHO spokesperson said Wednesday that experts are aware of the study and will continue to examine all evidence. When the WHO approved the study, a WHO expert stated that there was no reason for it to work differently for the elderly.
Sinopharm has developed two vaccines similar to this one. According to the state-owned Chinese company, almost all of the final-stage clinical trial participants were younger than 60. Researchers also found that there wasn't enough evidence to prove the vaccines are safe for the elderly. The Beijing Institute vaccine was 78% effective overall.
Many people in Hungary were concerned about the shot and sought private anti-body tests. Eventually the capital city of Budapest offered free testing to elderly residents as part a bid to ratchet up pressure on the government to conduct its own wider survey and provide booster shots to those who need them.
After initially refusing to respond to calls for a government response regarding efficacy concerns, including from Tamas Ferenci and Balazs Sarkadi (authors of the antibody study), Prime Minister Viktor Orban finally gave in last week to growing public anger. He said that the government would offer its citizens an optional third shot.
However, his office stated that all vaccines approved by Hungary are safe and effective.
The United Arab Emirates and Bahrain both announced in May that they, too, would offer a third dose of Sinopharm amid concerns about an insufficient antibody response. Bahrain recommended that people over 50 and some other vulnerable people receive Pfizer-BioNTech's vaccine as their booster regardless of whether they got Sinopharm initially.
CNBG, the Sinopharm subsidiary responsible for the Beijing Institute, stated that a third dose was not included in the company's clinical guidance.
It is not known how many doses have been exported from the Beijing Institute Sinopharm vaccine. China exported 500 million doses of vaccines during the first half of this year. The company is also one of China's major COVID vaccine manufacturers, alongside Sinovac.
Global Alliance for Vaccines and Immunization ordered 550 Million doses of vaccines from these two companies for its U.N.-backed COVAX program.
Both Sinopharm vaccines have been widely used in China, even among the elderly. In April, the National Health Commission of China stated that shots offer some protection, despite acknowledging that two vaccines from Sinopharm and one other found fewer antibodies in older people.
Beata Englohner, 76, became concerned about her mother's health after learning that those who were vaccinated against Sinopharm had no antibodies.
Englohner created a Facebook group to pressure the government to address this issue. She is optimistic that Hungary will provide a third dose.
She said, "We are very happy that we achieved our goal and that we were heard." "We are a little afraid that we won't get what we have already received."