Written by Dr David Owens
What type of vaccine is Sinovac?
Answer: Sinovac is an inactivated vaccine
Sinovac is a traditional inactivated vaccine. This vaccine can be stored in a standard fridge making widespread use easier than newer mRNA vaccines. It is given as 2 shots 28 days apart. The Hong Kong expert committee released a summary of the scientific committee findings. The report is available here.
Is Sinovac an effective vaccine?
The WHO approved Sinovac vaccine on the basis of a large phase 3 trial in Brazil which showed that two doses, administered at an interval of 14 days, had an efficacy of 50.7% against symptomatic SARS-CoV-2 infection, 100% against severe COVID-19, and 100% against hospitalization starting 14 days after receiving the second dose. A study published in the Lancet, of 11,000 volunteers in Turkey, showed 83.5% efficacy in preventing symptomatic disease. This study was in mostly younger patients and had a short follow up because the vaccine was approved for emergency use during the study period. We do not yet have large population studies of effectiveness.
Is Sinovac a safe vaccine?
The WHO strategic advisory group of experts on immunization (SAGE) has analysed the safety data for Sinovac and approved the vaccine for people over 18 years old. Safety monitoring is ongoing and large numbers of inactivated vaccines have now been given worldwide, especially in China.
Does Sinovac vaccine have side effects?
Answer: Yes but the vast majority are mild and self-limiting
The following are the reported incidence for side effects with Sinovac:
|Side Effects||May Affect|
|≥ 10% people|
|1% - 10% people|
|0.1% - 1% people|
|0.01% - 0.1% people|
Mild side effects are relatively common. In a recent survey of OT&P patients, only 2 out of 3,233 patients indicated that the side effects would prevent them from taking another vaccination. In our survey, mild side effects were less common with Sinovac than with the BioNTech vaccine. We have summarised the evidence of side effects of Covid vaccines in another article.
Does Sinovac prevent transmission of COVID-19?
Answer: No, there may be a small reduction in transmission
There is no evidence that Sinovac prevents the transmission of the SARS-Cov-2 virus. There is a possibility of a small reduction in transmission although the evidence for reduction is transmission is better for the mRNA vaccines. The impact of transmission is also less for the newer variants.
Is Sinovac effective against the Delta Variant?
Answer: Yes but to a reduced degree
Reports from China suggest that Sinovac is 59% effective against the Delta variant compared to 70.2% against moderate disease. Public health officials have reported improved effectiveness against Delta following a booster shot.
Can children have Sinovac?
In Hong Kong, Sinovac is licensed for individuals aged 18 and older. Sinovac has been given to children and adolescents in China and other countries with no reported increase in side effects. However, Sinovac contains Aluminium Hydroxide as an adjuvant and as yet there have been no large peer-reviewed trials of safety in children.
We have written another article on Covid vaccinations for children. The arguments for vaccinating children are balanced. Currently there is more peer-reviewed evidence for BioNTech than for Sinovac in children.
Can pregnant and lactating mothers have Sinovac?
In Hong Kong, Sinovac is not recommended to pregnant or lactating mothers. BioNTech is given internationally. In Hong Kong, the CHP advises pregnant and lactating mothers to discuss the risk-benefit of BioNTech vaccination with their doctor.
Can the Sinovac vaccine cause infertility?
There is no scientific evidence to suggest that the Covid vaccines can cause infertility, indeed there is good evidence that the vaccines have no impact on fertility. Various reports linking vaccination to infertility on social media are examples of misinformation.
Do I need a body check before I have a COVID-19 Vaccine?
Would you have a body check before having a flu jab? People who have underlying medical conditions should ideally always have them controlled. Individuals with other illnesses are generally at greater risk of COVID-19 and it is even more important that they are vaccinated.
I have high blood pressure/diabetes, can I have Sinovac?
If you have high blood pressure or diabetes, it should ideally be controlled but it is even more important for you to be vaccinated.
Does Sinovac vaccine reduce the impact of Long Covid?
Answer: Probably, but we do not yet have enough evidence to be certain
Long Covid is posing a significant burden to health systems. There is increasing evidence that vaccination significantly reduces the incidence of Long Covid. We do not yet have evidence for this benefit specifically for Sinovac but it seems likely that this is a result of vaccinations in general. More evidence is needed to be certain.
Interested in BioNTech vaccine? Check out our article BioNTech vaccine in 12 easy questions.
In a further article, we compare the vaccines head-to-head and ask which is the best vaccine.
1. Scientific Committee on Emerging and Zoonotic Diseases and Scientific Committee on Vaccine Preventable Diseases. Centre for Health Protection. (2021, September 15). Retrieved September 16, 2021, from https://www.chp.gov.hk/files/pdf/consensus_interim_recommendations_on_the_use_of_covid19_vaccines_in_hk_15sept21.pdf.