A World Health Organization (WHO) official said on Tuesday that China's widely used coronavirus vaccine, Sinopharm and Sinovac, still offer some protection against severe illness caused by the infection despite contradicting information spreading worldwide.
The official said that the Chinese treatments can also reduce hospitalization and death rates caused by the spreading Omicron variant despite a decline in protective antibodies. The WHO official, identified as incident manager Abdi Mahamud, made his assessment just days after several preliminary laboratory studies.
Sinovac Against Omicron
The scientific reviews indicated that three doses of Sinovac did not produce sufficient antibodies to prevent infection from the highly transmissible new variant of the coronavirus. One study conducted by researchers from Yale University, the Dominican Republic's health ministry, and other institutions concluded that two doses of the Sinovac vaccine and a booster shot from Pfizer were not enough to stop a person from being infected with the Omicron variant.
On Tuesday, Mahamud said that, while the Omicron variant was evasive of antibodies and could still cause infection, evidence suggested that the vaccines still provided protection against severe illness, hospitalization, and death, the South China Morning Post reported.
The situation comes after researchers from the University of Hong Kong and the Chinese University of Hong Kong conducted a study that found three doses of the Sinovac vaccine did not provide enough antibodies to fight off the Omicron variant. The analysis revealed that Pfizer-BioNTech was much more effective in keeping the infection at bay.
The researchers found that a third dose of the Pfizer vaccine administered after two initial doses of the Sinovac vaccine provided "protective levels" of antibody against the Omicron variant. Authorities from Pfizer and BioNTech said that their vaccine was able to neutralize the new Omicron variant in a laboratory test using a three-shot course.
The recent study was funded by the Health and Medical Research Fund and the Government of Hong Kong. The released statement did not specify how many samples were used in the study and Sinovac did not immediately provide comments regarding the issue, Reuters reported.
Efficacy of the Vaccine
Another study, conducted by the Pontifical Catholic University in Chile (UC), showed that the Sinovac vaccine booster dose had the potential to activate cellular immunity against the Omicron variant on subjects who were previously given two doses of the same vaccine.
Millennium Institute on Immunology and Immunotherapy director Prof. Dr. Alexis M. Kalergis led the study whose objective was to assess whether the immunity activated by the Chinese coronavirus vaccine booster was able to identify the Omicron variant. In a statement released by Pharmaniaga on Saturday, Dr. Kalergis said that people who received the Sinovac vaccine booster had T-cell levels that were activated against the new variant.
"This shows that the vaccine contains antigens that are found in the Omicron variant. The results show that when T-lymphocytes come in contact with the Omicron variant, they are able to produce gamma interferon which is capable of killing the dangerous virus," said Alexis, The Star reported. It was also found that Chile researchers cooperated with the Catholic University, the University of Chile, the La Jolla Institute of Immunology in California, and Sinovac in China.