Sinovac Vaccine CoronaVac(Discontinued) Comprehensive guide on Side Effects, Efficacy and Reservation Procedures

CoronaVac is a vaccine used for preventing COVID-19 caused by SARS-CoV-2 virus infection. CoronaVac contains inactivated (killed) SARS-CoV-2 viruses, which causes the immune system (the body’s natural defences) to produce antibodies and blood cells that work against the virus, so giving protection against COVID-19.

In a Phase 3 clinical trial conducted in Brazil, the study estimated vaccine efficacy for prevention of different disease endpoints after receiving 2 doses of CoronaVac and 14 days apart:

From 4 August 2022 onwards, children aged 6 months to less than 3 years old can receive CoronaVac vaccine.

Interval : The interval between the first two doses should be at least 28 days apart and the third dose to be given at least 90 days after the second dose.For immunocompromised children, the interval between the first two doses is at least 28 days, and the third dose to be given 28 days after the second dose.

More: Point to Note and Frequently Asked Questions on COVID-19 Vaccination for Children and Adolescents

The benefit of using CoronaVac generally exceeds the risk of not suing any vaccines in persons aged 60 and above. Phase I and II data on individuals aged 60 and above showed that the vaccine is safe and immunogenic.

The clinical data of pregnant and lactating women are not available at present. However, this vaccine is an inactivated vaccine with an adjuvant that is commonly used in many other vaccines with a well-documented safety profile, such as Hepatitis B and Tetanus vaccines, including in pregnant women. Therefore, WHO recommends the use of the Sinovac-CoronaVac (COVID-19) vaccine in pregnant women when the benefits of vaccination to the pregnant woman outweigh the potential risks.

Vaccine effectiveness is expected to be similar in lactating women as in other adults. WHO recommends the use of the COVID-19 vaccine Sinovac-CoronaVac in lactating women as in other adults and does not recommend discontinuing breastfeeding after vaccination.

• Due to the insufficient data of persistence of protection induced by this vaccine, necessary protective measures should be taken in line with prevention and control of the COVID-19 epidemic.
• For patients with acute diseases, acute exacerbation of chronic diseases, severe chronic diseases, atopy and fever, the vaccine should be used with caution: if necessary, delay vaccination after doctor's evaluation.
• For patients with diabetes, or history of convulsions, epilepsy, encephalopathy or mental illness, or family history of these diseases, the vaccine should be used with caution.
• For patients with thrombocytopenia or hemorrhagic diseases, intramuscular injection of this product may cause bleeding, so it should be used with caution.
• The safety and efficacy data of this product on people with impaired immune function(such as malignant tumor, nephrotic syndrome, AIDS patients) have not been obtained, and the vaccination of this product should be based on individual considerations.
• People who inject human immunoglobulin should receive this vaccine at least one month apart to avoid affecting the immune effect.
• Do not use it again if there is any adverse reaction of nervous system after vaccination.
• Like other vaccines, the protective effect may not reach 100% for all recipients.
• Observe for 15 minutes after vaccination.

If you get any serious side effects, you should talk to your doctor, pharmacist or nurse. Healthcare professionals will offer advice, manage your condition and make proper assessment for reporting to the Department of Health.

The Department of Health has an adverse drug reaction reporting system that receives adverse events following immunization reports to monitor the safety of COVID-19 vaccines, and if necessary, healthcare professionals will report any adverse event following immunization that is medically significant to the Department of Health for continuous monitoring of the safety of the vaccine.

• History of allergic reaction to CoronaVac or other inactivated vaccine, or any component of CoronaVac (active* or inactive* ingredients, or any material used in manufacturing process);
• Previous severe allergic reactions to the vaccine (eg, acute anaphylaxis, angioedema, dyspnea, etc.);
• Severe neurological conditions (eg, transverse myelitis, Guillain-Barré syndrome, demyelinating diseases, etc.);
• Uncontrolled severe chronic diseases; (Note: Common chronic diseases include diabetes, hypertension and coronary heart disease, etc. If your chronic disease is stable, you should receive the vaccine for protection because chronically-ill persons have a higher risk of serious illness or death from COVID-19 infection. If you are unsure about your condition, or if there is a recent change in your disease/ recent adjustment of drugs/ recent need for referral, etc, please discuss with your family doctor or attending doctor the appropriate time for vaccination.)

* Including inactivated SARS-CoV-2 Virus (CZ02 strain), aluminium hydroxide, disodium hydrogenphosphate dodecahydrate, sodium dihydrogen phosphate monohydrate, and sodium chloride.1 Following information provided by drug company

Strategic Advisory Group of Experts on Immunization (SAGE) recommends the use of Sinovac-CoronaVac vaccine as 2 doses (0.5 ml) given intramuscularly. For individuals aged 60 and above, a third, additional dose may be considered as an extension of the primary series. For those with severe and moderately immunocompromised persons should be offered an additional dose of vaccine to reduce the risk of severe COVID-19.

More: How many doses of COVID-19 vaccine are recommended for me?

CoronaVac is administered as a series of two doses. You may get some protection from the first dose, and having the second dose will give you the best protection against the virus. It takes time after vaccination for antibodies to develop in the body and offer protection against COVID-19. Individuals may not be protected effectively until 14 days after their second dose of vaccine.

A study conducted by the University of Hong Kong in February 2023 examined the efficacy of COVID-19 vaccines in preventing infection with the SARS-CoV-2 Omicron variant. Via a serological survey of 5,310 blood donors and other volunteers, the researchers estimated the following results :

The results indicate that receiving CoronaVac vaccine as a booster dose is effective in preventing SARS-CoV-2 Omicron BA.2 infection in the short-term. However, the efficacy of CoronaVac vaccine is likely to decline rapidly over time.