Sinovac and Sinopharm, the flop of inactivated virus vaccines against Omicron. Report Nature
Inactivated Covid virus vaccines Sinovac and Sinopharm account for nearly 5 of the more than 11 billion doses delivered globally and with Omicron this could be a problem. Here's what Nature says
China has produced them and authorized their administration in children aged 3 years and over, of the more than 11 million doses delivered worldwide Sinovac and Sinopharm represent almost 5 billion, but more and more studies, writes Nature , show that both provide little. or no protection against the Omicron variant.
HOW EFFECTIVE ARE INACTIVATED VIRUS VACCINES
Inactivated virus vaccines that are stable and relatively easy to manufacture, such as Sinovac and Sinopharm , contain chemically treated SARS-CoV-2 particles to prevent infection. According to studies cited in the journal Nature , many of the people who received two doses of either vaccine fail to produce antibodies that can counter Omicron, and after a third dose, neutralizing antibody levels tend to remain low.
These results, it says, are prompting many scientists and researchers to re-evaluate the role of inactivated virus vaccines in the global fight against Covid.
NOT ONLY SINOPHARM AND SINOVAC
In addition to the nearly 5 billion doses of Sinovac and Sinopharm, distributed as part of China's global vaccine diplomacy, UK data-tracking company Airfinity reports that more than 200 million doses of other inactivated virus vaccines have also been delivered such as the Covaxin of India, the COVIran Barekat of Iran and the QazVac of Kazakhstan.
COMPARING STUDIES
Hong Kong researchers analyzed the blood of 25 people who had received two doses of Sinovac and not one of them had antibodies capable of neutralizing Omicron. The company quickly challenged the study and said they had internal data indicating that 7 out of 20 people had developed them.
Other studies involving people immunized with Covaxin2, manufactured by Bharat Biotech of Hyderabad, India, and BBIBP-CorV3, manufactured by Chinese state-owned Sinopharm, in Beijing, concluded that inactivated virus vaccines retain some potency against Omicron – although, as researchers from the Translational Health Science and Technology Institute in Faridabad in India said, in their study 2, immune responses were "sub-optimal".
Although the results on the effectiveness of these vaccines against Omicron are not the most encouraging, some experts such as Murat Akova, an infectious disease specialist at Hacettepe University School of Medicine in Ankara, say they should protect against severe disease.
WHAT HAPPENS WITH A DIFFERENT THIRD DOSE
Given an mRna vaccine as a third dose, protection appears to be better, but some believe it is still not sufficient against Omicron.
Akiko Iwasaki, a viral immunologist at Yale School of Medicine in New Haven Connecticut, and other colleagues who studied blood samples from 101 who had received two doses of Sinovac followed by an mRNA booster found that 80% of these had some "blocking activity" against Omicron, but the antibody levels were not much higher than in another group given two doses of the mRNA vaccine and no booster.
This is a machine translation from Italian language of a post published on Start Magazine at the URL https://www.startmag.it/sanita/sinovac-e-sinopharm-il-flop-dei-vaccini-a-virus-inattivato-contro-omicron-report-nature/ on Sun, 16 Jan 2022 15:02:10 +0000.