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Sinovac Side Effects, Effectivity, and Safety

Sinovac Side Effects, Effectivity, and Safety

By numbers, the Sinovac vaccine is, by far, the most plentiful vaccine in the Philippines. Of the 64.9 million total vaccine doses delivered to the Philippines as of Sept 20, 2021, 36 million are the Sinovac vaccine1. It’s understandable to have questions, especially when it comes to life-threatening diseases like COVID-19 and the vaccines that protect us. Is Sinovac safe? Is it effective? Should I worry about Sinovac side effects? We’ll answer all of these questions here with facts and recommendations from experts.

How Vaccines Work

Before we look at the vaccine’s effectiveness and Sinovac side effects, it’s important to understand how vaccines protect us.

When your body encounters a virus or a bacteria, at first, it doesn’t know what to do. And this invasion, or infection, makes you ill. Over time, your immune system learns how to fight the infection. More importantly, it remembers what to do the next time you get infected. This is called an immune response.

All vaccines work in the same way: They imitate an infection in your body to train it to develop an immune response2.

Since vaccines are just copycats of the virus they are imitating, you cannot get ill. But you can expect some mild side effects to occur.

All About Sinovac

Sinovac Biotech is the producer of the CoronaVac vaccine for COVID-19. It is a Chinese pharmaceutical company based in Beijing.

CoronaVac, commonly referred to as the Sinovac vaccine, was validated for Emergency Use listing by the WHO in June 20203. It is now approved for use in 40 countries4.

Is Sinovac Safe?

Yes, Sinovac is safe. It has been thoroughly assessed and approved by the WHO Strategic Advisory Group of Experts (SAGE). It has also been proven to be safe in phase 3 trials5. At this point in the pandemic, millions have taken Sinovac in the Philippines as well as all over the world.

The DOH has approved the use of the Sinovac vaccine.

The Department of Health has assessed the Sinovac vaccine and, together with the FDA, approved it for emergency use for persons aged 18 to 596.

The FDA has approved Sinovac.

The Philippine FDA has given Sinovac’s vaccine emergency use authorization7. A total of 8 vaccines have emergency use authorization, including Pfizer-BioNTech’s COVID-19 Vaccine (Comirnaty) and ChAdOx1-S by AstraZeneca.

How Effective Is Sinovac?

When it comes to effectivity, the vaccine is 51% effective against infection if two doses are taken, at an interval of 14 days. More importantly, the Sinovac vaccines were 100% effective in preventing severe COVID-19, and 100% effective in preventing hospitalization5.

Sinovac Side Effects

According to The Lancet, based on phase 1 and trials, you can expect the following side effects after taking the Sinovac vaccine8:

Injection Site Pain

The most common of the Sinovac side effects is injection site pain. Those who received the vaccine in trials reported some kind of pain within 28 days of taking the shot.

Fatigue, Diarrhea, Muscle Pain

Other Sinovac side effects include fatigue, diarrhea and muscle pain. These effects were mild and usually lasted for 2 days.

In addition, the number of people who reported a fever as one of the Sinovac side effects was lower compared to other vaccines such as Moderna or Astrazeneca8.

Key Takeaway

Sinovac is safe. The WHO, as well as the Philippines’ DOH and FDA, have all approved Sinovac. It has undergone stringent phase 3 trials and is also in use in over 40 countries worldwide.

If you are about to receive the vaccine, expect some Sinovac side effects. That is simply how vaccines work. Sinovac side effects include pain in the injection site, fatigue, diarrhea and muscle pain.

Learn more about Coronavirus here.

Hello Health Group does not provide medical advice, diagnosis or treatment.


1 TRACKER: The Philippines’ COVID-19 vaccine distribution, https://www.rappler.com/newsbreak/data-documents/tracker-covid-19-vaccines-distribution-philippines, Accessed Sept 29, 2021

2 Understanding How Vaccines Work, https://www.cdc.gov/vaccines/hcp/conversations/understanding-vacc-work.html, Accessed Sept 29, 2021

3 Sinovac COVID-19 vaccine: What are the side effects? https://www.medicalnewstoday.com/articles/sinovac-covid-19-vaccine-what-are-the-side-effects, Accessed Sept 29, 2021

4 Sinovac: CoronaVac, https://covid19.trackvaccines.org/vaccines/7/, Accessed Sept 29, 2021

5 The Sinovac-CoronaVac COVID-19 vaccine: What you need to know, https://www.who.int/news-room/feature-stories/detail/the-sinovac-covid-19-vaccine-what-you-need-to-know?gclid=Cj0KCQjwqKuKBhCxARIsACf4XuHJq0lH-73_fhgEjbuFWYgCb17jtMn0J46-GnOq92DiO41_8GiyJAMaAsmAEALw_wcB, Accessed Sept 29, 2021

6 HTAC GUIDANCE FOR THE GENERAL PUBLIC: COVID-19 VACCINE SINOVAC, https://hta.doh.gov.ph/2021/05/04/htac-guidance-for-the-general-public-covid-19-vaccine-sinovac/, Accessed Sept 29, 2021


https://www.fda.gov.ph/wp-content/uploads/2021/06/Reports-of-Suspected-Adverse-Reaction-to-COVID-19-Vaccines-as-of-20-June-2021.pdf, Accessed Sept 29, 2021

8 Safety, tolerability, and immunogenicity of an inactivated SARS-CoV-2 vaccine in healthy adults aged 18–59 years: a randomised, double-blind, placebo-controlled, phase 1/2 clinical trial, https://www.thelancet.com/article/S1473-3099(20)30843-4/fulltext, Accessed Sept 29, 2021

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Written by Vincent Sales Updated Sep 29, 2021
Fact Checked by Hello Doctor Medical Panel