it's time for me to get vaccinated with sinovac vaccine. I am actually a little bit nervous, about its effectiveness, I am not a docotor and I have no idea what's behind it. I am worrying that it might damage my body, like my brain (it might be a stupid idea). what do you think? is this vaccine safe?


You may not have had a chance to see this from the WHO: https://www.who.int/news-room/feature-stories/detail/the-sinovac-covid-19-vaccine-what-you-need-to-know

"The WHO Strategic Advisory Group of Experts (SAGE) on Immunization has issued Interim recommendations for the use of the inactivated COVID-19 vaccine, Sinovac-CoronaVac, developed by Sinovac/China National Pharmaceutical Group.


Is it safe?

SAGE has thoroughly assessed the data on quality, safety and efficacy of the vaccine and has recommended its use for people aged 18 and above.

Safety data is currently limited for persons above 60 years of age (due to the small number of participants in clinical trials).

While no differences in safety profile of the vaccine in older adults compared to younger age groups can be anticipated, countries considering using this vaccine in persons older than 60 years should maintain active safety monitoring.

As part of the EUL process, Sinovac has committed to continuing submit data on safety, efficacy and quality in ongoing vaccine trials and rollout in populations, including in older adults.

How efficacious is the vaccine?

A large phase 3 trial in Brazil showed that two doses, administered at an interval of 14 days, had an efficacy of 51% against symptomatic SARS-CoV-2 infection, 100% against severe COVID-19, and 100% against hospitalization starting 14 days after receiving the second dose. Does it work against new variants of SARS-CoV-2 virus?

In an observational study, the estimated effectiveness of Sinovac-CoronaVac in health workers in Manaus, Brazil, where P.1 accounted for 75% of SARS-CoV-2 samples was 49.6% against symptomatic infection (4). Effectiveness has also been shown in an observational study in Sao Paulo in the presence of P1 circulation (83% of samples).

Assessments in settings where the P.2 Variant of Concern was widely circulating – also in Brazil - estimated vaccine effectiveness of 49.6% following at least one dose and demonstrated 50.7% two weeks after the second dose. As new data becomes available, WHO will update recommendations accordingly.

SAGE currently recommends using this vaccine, according to the WHO Prioritization Roadmap."

Also note that this vaccine is a killed-virus type of vaccine, different from the adenovirus-vector types of vaccines that have been in the news recently due to possible very very rare blood clot issues.

More detailed resources:

"Interim recommendations for use of the inactivated COVID-19 vaccine, CoronaVac, developed by Sinovac" https://www.who.int/publications/i/item/WHO-2019-nCoV-vaccines-SAGE-recommendation-Sinovac-Coronavac

"Annexes to the recommendations for use of the Sinovac-CoronaVac vaccine against COVID-19: Grading of evidence, Evidence to recommendation tables" https://www.who.int/publications/i/item/WHO-2019-nCoV-vaccines-SAGE_recommendation-Sinovac-CoronaVac-annexes-2021.1

"Background document on the inactivated vaccine Sinovac-CoronaVac against COVID-19" https://www.who.int/publications/i/item/WHO-2019-nCoV-vaccines-SAGE-recommendation-Sinovac-CoronaVac-background

  • 51% is too less, so i guess it's not effective and might cause some bad side effects in long run, that's what this 51% tells me Jun 8 at 13:03
  • 1
    There is nothing about "some bad side effects" in the above. The 51% says that vaccinated people were roughly half as likely as unvaccinated people to develop any Covid symptoms, and the 100% means vaccinated people were 100% protected against having to be hospitalized from Covid and 100% protected against getting a severe case of Covid. That is the opposite of "not effective".
    – Armand
    Jun 8 at 21:32

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