[MISLEADING] Does the Sinovac vaccine contain excessive formaldehyde?

Screenshot of the Facebook post.

The Claim and Our Verdict

• The claim:A screenshot was shared Oct. 31, 2021 on Facebook, along with a claim that the Sinovac vaccine contains excessive formaldehyde.
• Fact-checking:
  • Similar posts were found on Facebook and Weibo. The Sinovac Biotech Ltd. (Sinovac) has attracted the public’s attention due to its Sinovac COVID-19 vaccine (branded as CoronaVac). In media and public discussions, the “Sinovac vaccine” often refers to the COVID-19 vaccine, CoronaVac, developed and manufactured by Sinovac. The comments on the post also show that the public considers the “Sinovac vaccine” as the “Sinovac COVID-19 vaccine.”
  • The post claims, “The Sinovac vaccine contains 0.009–0.01250g/ml formaldehyde.” This actually comes from a patent of Hepatitis A vaccine applied for by Sinovac in 2014. The formaldehyde in the Sinovac Hepatitis A vaccine is not associated with the COVID-19 vaccine. Formaldehyde is a naturally occurring organic compound that could be used as an additive in vaccine manufacturing to inactivate toxins and pathogens. When used in large quantities, it could be toxic and dangerous to the human body.
  • According to the China National Health Commission, the Sinovac COVID-19 vaccine is inactivated by β-propiolactone, another organic compound used to inactivate a wide variety of viruses, not
  • According to Sinovac’s official website., the fact sheet of the vaccine published by the Hong Kong government, and the World Health Organization (WHO), the Sinovac COVID-19 vaccine does not contain formaldehyde.
  • The claim uses the “Sinovac vaccine” to refer to vaccines other than the Sinovac COVID-19 vaccine without explanation. In the context of the current situation of the COVID-19 pandemic, it will mislead the public to believe that the Sinovac COVID-19 vaccine contains excessive formaldehyde.
• Our ruling: Therefore, we rate the claim as MISLEADING.

News Brief

A screenshot was shared Oct. 31, 2021 on Facebook, along with a claim that the Sinovac vaccine contains excessive formaldehyde. The screenshot reads, “According to the Chinese Pharmacopoeia, the content of formaldehyde is 50 µg/ml. The Sinovac vaccine contains 0.009–0.01250 g/ml formaldehyde, which is 9000–12500 µg/ml. This means that the formaldehyde content in the vaccine is 180–250 times the upper limit set by the Chinese Pharmacopoeia.”

Formaldehyde is a naturally occurring organic compound that could be used as an additive in vaccine manufacturing to inactivate toxins and pathogens. When used in large quantities, it could be toxic and dangerous to human body.

As of the issuance of this report, the post had been shared twice, and had received 4 likes or reactions.

Fact-checking

The source information and background of the claim

A keyword search found similar posts on Facebook and Weibo. A reverse image search found the statement, “The Sinovac vaccine contains 0.009–0.01250 g/ml formaldehyde,” actually comes from a patent applied by the Sinovac Biotech Ltd. (Sinovac) in 2014, titled as “A method for inactivating virus in vaccine production.” The figure represents the formaldehyde content of the inactivated solution added during the manufacturing of the vaccine. The patent document can be found on “Tianyancha,” a business inquiry platform in mainland China. The document shows that formaldehyde solution is indeed added in the manufacturing process. The final concentration range of formaldehyde in the inactivated solution was 0.009 to 0.0125 g/ml. However, this patent is about inactivating hepatitis A virus in vaccine production and does not mention anything related to the COVID-19 vaccine.

Screenshot of the patent page on Tianyancha.

Screenshot of the patent, “A method to inactivate hepatitis A virus in vaccine production.”

In summary, the source information of the post is only a patent applied for in 2014 by Sinovac. The vaccine involved in the patent is not the Sinovac COVID-19 vaccine.

Does Sinovac COVID-19 vaccine contain formaldehyde?

On further inquiry, HKBU FactCheck Service found the document, titled “Technical Guideline for the Inoculation of COVID-19 Vaccines (First Edition),” published by the China National Health Commission. The document shows conditional approval is given to the COVID-19 inactivated vaccine manufactured by Sinovac. “African green monkey kidney (Vero) cells are used for virus cultivation and amplification. The virus is inactivated with β-propiolactone, retaining antigenic components to induce an immune response, and aluminum hydroxide adjuvant is added to improve immunogenicity,” according to the document. Thus, formaldehyde is not used to inactivate the virus for the Sinovac COVID-19 vaccine.

Screenshot of the document, “Technical Guideline for the Inoculation of COVID-19 Vaccines (First Edition).”

For the composition of the inactivated COVID-19 vaccine, Dr. Li Ming, deputy director in the department of respiratory medicine at the Shanghai Tenth People’s Hospital, explained in an interview, “the novel coronavirus’s inactivating agent is not formaldehyde, but β-propiolactone. Compared with formaldehyde, β-propiolactone has two advantages: first, it can directly destroy the virus, but does not affect its immunogenicity; second, it can be quickly dissolved in water or vaccine solution and decomposed into non-toxic substances. There are indeed some additives in the COVID-19 vaccine, such as sodium phosphate, sodium chloride, aluminum hydroxide, and so on. These additives are the common pharmaceutical preparations, which are not toxic in clinical use. The content is relatively small, so they will not cause harm to the human body.” Li’s explanation, corresponding to the document released by the China National Health Commission, shows that the Sinovac COVID-19 vaccine is inactivated by β-propiolactone and does not contain formaldehyde.

 Sinovac’s official website shows the content of the Sinovac COVID-19 Vaccine on its package. It shows that the vaccine contains “inactivated SARS-CoV-2 (the coronavirus that causes COVID-19) virus antigen (CZ02 strain), aluminum hydroxide, sodium dihydrogen phosphate, disodium hydrogen phosphate, sodium chloride. No preservative in this product.” According to the fact sheet of the vaccine published by the Hong Kong government and background document of the vaccine published by the World Health Organization (WHO), the Sinovac COVID-19 vaccine does not contain formaldehyde, either.

In summary, there is no evidence showing that the Sinovac COVID-19 vaccine contains formaldehyde.