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The need for clarity on the safety and efficacy of China’s vaccines has become more urgent after Sinopharm revealed that it had already vaccinated about a million people even before the end of clinical trials. The campaign has alarmed foreign scientists who say it exposes people to undue risk.
Chinese officials have repeatedly assured the public that the country’s coronavirus vaccines are safe, though they provide few details. Last month, Liu Jingzhen, president of Sinopharm said that none of the people who had received the company’s vaccines had experienced adverse reactions. He said “only a few had mild symptoms.”
The road to a coronavirus vaccine
Words to know about vaccines
Confused by all the technical terms used to describe how vaccines work and are researched? Let’s help:
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- Adverse event: A health problem that arises in volunteers in a clinical trial of a vaccine or drug. An adverse event is not always caused by the treatment tested in the trial.
- Antibody: A protein produced by the immune system that can attach itself to a pathogen such as coronavirus and prevent it from infecting cells.
- Emergency use approval, license and authorization: Medicines, vaccines and medical devices cannot be sold in the United States without winning approval of the Food and Drug Administration, also known as bachelor’s degree. After a company submits the results of clinical trials to the FDA for consideration, the agency decides whether the product is safe and effective, a process that generally takes many months. If the country faces an emergency, such as a pandemic, a company can request a emergency use authorization, which can be awarded considerably faster.
- Fund rate: How often a health problem, known as an adverse event, arises in the general population. To determine whether a vaccine or drug is safe, researchers compare the rate of adverse events in a trial with the rate in the background.
- Effectiveness: The benefit that a vaccine provides compared to a placebo, measured in a clinical trial. To test a coronavirus vaccine, for example, researchers compare how many people in the vaccinated and placebo groups get Covid-19. Efficacy, on the other hand, is the benefit that a vaccine or drug provides in the real world. The effectiveness of a vaccine may be less or greater than its effectiveness.
- Phase 1, 2 and 3 trials: Clinical trials usually take place in three stages. Phase 1 trials generally involve a few dozen people and are designed to look at whether a vaccine or drug is safe. Phase 2 trials, involving hundreds of people, allow researchers to test different doses and collect more measurements on the effects of the vaccine on the immune system. Phase 3 trials, involving thousands or tens of thousands of volunteers, determine the safety and efficacy of the vaccine or drug by waiting to see how many people are protected from the disease for which it is designed.
- Placebo: A substance that has no therapeutic effect, which is often used in a clinical trial. To see if a vaccine can prevent Covid-19, for example, researchers can inject the vaccine into half of their volunteers, while the other half receive a saltwater placebo. They can then compare how many people in each group are infected.
- Post-marketing surveillance: The monitoring that takes place after a vaccine or medicine has been approved and is regularly prescribed by doctors. This monitoring generally confirms that the treatment is safe. In rare cases, it detects side effects in certain groups of people that were missed during clinical trials.
- Preclinical research: Studies that are carried out before the start of a clinical trial, generally involving experiments in which a treatment is tested on cells or animals.
- Viral vector vaccines: A type of vaccine that uses a harmless virus to introduce immune-boosting ingredients into the human body. Viral vectors are used in several experimental Covid-19 vaccines, including those developed by AstraZeneca and Johnson & Johnson. Both companies are using a common cold virus called adenovirus as a vector. Adenovirus carries coronavirus genes.
- Test protocol: A series of procedures that will be carried out during a clinical trial.
In October, Zheng Zhongwei, a senior health official, said the government had set up a “tracking program” to track people who had been vaccinated, although he did not give details.
Sinovac Biotech, a Beijing-based private vaccine manufacturer, has already started exporting its vaccines to countries such as Indonesia and Brazil. Sinopharm, which has another vaccine in late testing, has said it is preparing to deliver 500 million doses worldwide, according to the state-run Science and Technology Daily newspaper.
It is unclear whether the Emirates will begin using the Chinese vaccine, which Sinopharm developed with the Beijing Institute of Biological Products, for mass inoculations. The government had already approved the vaccine for emergency use in September for front-line workers at risk of contracting Covid-19.
Some other countries where Sinopharm is conducting trials have Chinese vaccines to help protect their populations. Morocco says it is preparing to vaccinate 80 percent of its adults, initially relying on a Sinopharm vaccine, though it would wait for China to approve the vaccine, according to Médias24, a Moroccan news website.
Chinese vaccines are also attractive to developing countries because they could be easier to distribute. Sinopharm has said that its vaccines need to be refrigerated at temperatures of just 2 to 8 degrees Celsius (or 35 to 46 degrees Fahrenheit) and could remain stable for up to three years. In contrast, Pfizer and Moderna vaccines, which are made from genetic materials that fall apart when thawed, require industrial freezers, making transportation and storage difficult.
