SINOVAC Biotech Ltd. (NASDAQ: SVA) (“SINOVAC” or the “Company”), a leading provider of biopharmaceutical products in China, collaborating with IQVIA Brazil published an article on December 17 titled “Safety Profile of COVID-19 Vaccines in Pregnant and Postpartum Women in Brazil.” on medRxiv, the preprint server of health sciences.
In the study, from April-August 2021, 252,430 doses of CoronaVac® were administered to pregnant and postpartum women between the ages of 20-40. A total of 3,333 cases were reported with adverse events following immunization (AEFI). The result showed that the COVID-19 inactivated vaccine CoronaVac developed by SINOVAC proved safe in pregnant and postpartum women. The study data also revealed that, compared with COVID-19 vaccines developed by other technical platforms, CoronaVac had a lower incidence rate of adverse events.
During the study period, 74.06% of the doses were given to those who are between 21 and 35 years old. Meanwhile, 76.66% of the doses were given during pregnancy. The AEFI surveillance data came from the Brazilian Surveillance Information System for Adverse Events (SI-EAPV).
Study results show that although the case fatality rate （CFR） of COVID-19 is lower than that of SARS and MERS, the virus is highly contagious. Most patients showed mild symptoms, still, around 20% of infected individuals developed into severe cases, even death. The elderly, people with underlying diseases, pregnant and postpartum women are more vulnerable to COVID-19.
Compared with non-pregnant women, pregnant women (infected with COVID-19) is more likely to develop into severe cases, increasing the risks of hospitalization, ICU, invasive ventilation, extracorporeal membrane oxygenation, and even death. However, at the current stage, there is still a lack of evidence on the safety and efficacy of vaccines among pregnant and postpartum women, especially the safety evidence of COVID-19 vaccines in pregnant and postpartum women. In view of this, it is crucial to establish a framework to surveillance vaccine safety among those high-risk group of population and provide appropriate advice for them.
According to Brazil's national COVID-19 immunization program (NIP), pregnant women are considered as a priority group of people for COVID-19 vaccination. Therefore, as early as March 2021, Brazil began to vaccinate this group and the CoronaVac® was the first vaccine approved to be applied in pregnant and postpartum women.
The data show that the mortality rate of pregnant and postpartum women caused by COVID-19 is relatively high in Brazil, vaccination is a very important strategy to reduce the impacts of COVID-19 on pregnant and postpartum women as well as their fetuses. Brazil has prioritized this group in its national COVID-19 immunization program, thus more evidence is required to prove the protective efficacy and safety of vaccines. In the perspective of this, the study filled the gap of the safety data in this specific group of population and provide scientific evidence for pregnant and postpartum women vaccination in Brazil, as well as other countries around the world.
In addition, to evaluate the safety of the second and booster doses, as well as using different types of vaccines as the second or booster dose of COVID-19 vaccine for pregnant and postpartum women is still necessary so that further evidence could be provided to support a better vaccination program.
SINOVAC Biotech Ltd. is a China-based biopharmaceutical company that focuses on the research, development, manufacturing and commercialization of vaccines that protect against human infectious diseases. SINOVAC's product portfolio includes vaccines against COVID-19, enterovirus71 (EV71), hepatitis A and B, seasonal influenza, 23-Valent pneumococcal polysaccharide ("PPV"), H5N1 pandemic influenza (avian flu), H1N1 influenza (swine flu), varicella and mumps. SINOVAC's COVID-19 vaccine, CoronaVac®, has been granted emergency use approval or conditional marketing authorization by over 40countries or regions worldwide. Healive®, the hepatitis A vaccine manufactured by the Company, has passed the assessment under WHO prequalification procedures in 2017. The EV71 vaccine, an innovative vaccine developed by SINOVAC against hand foot and mouth disease caused by EV71, was commercialized in China in 2016. In 2009, SINOVAC was the first company worldwide to receive approval for its H1N1 influenza vaccine, which it has supplied to the Chinese Government's vaccination campaign and stockpiling program. The Company is also the only supplier of the H5N1 pandemic influenza vaccine to the government stockpiling program. The Company is developing several new products including a Sabin-strain inactivated polio vaccine and combined vaccines. SINOVAC primarily sells its vaccines in China, while also exploring growth opportunities in international markets. The Company is seeking market authorization of its products in over 30 countries outside of China. For more information, please see the Company's website at www.sinovac.com.
After the enhanced immunization with the third dose of SINOVAC COVID-19 Vaccine, the spectrum breadth of the antibody improves and it has a good cross-neutralization effect on COVID-19 variant strains