As a doctor with 1.27 million followers on social media, I am often asked questions by my followers. In recent weeks, "Is the COVID-19 vaccine safe?" has been the most frequently asked question.

Followed by, "Will the vaccine effectively provide protection against the novel coronavirus?"

Maybe it is time to share some basic facts about vaccines. First, a vaccine is categorized as a kind of medicine, and like all similar products, safety is the topmost priority in its development and production.

When a pharmaceutical enterprise starts to research a new vaccine, it must do tests on animals first, then, should the results merit proceeding, clinical tests are conducted on human volunteers in Phase I trials, on more human volunteers in Phase II, and then all the tests are redone in Phase III.

In all these phases, safety is paramount and any vaccine candidate that fails the safety requirement in any phase will fail. Especially, in the Phase I clinical tests, there are studies done from all angles on safety and any vaccine candidate that does not perform well will not proceed to the next phase.

According to the official news releases, the five COVID-19 vaccines developed by Chinese enterprises have all performed well in their Phase III clinical tests, while the ones developed by US and German companies have similarly performed well in their tests. The safety of all these vaccines can be ensured.

Some who oppose vaccines list examples of children who have suffered from illnesses, even disabilities, after receiving vaccines. These examples are true, but they, intentionally or not, misrepresent the concept of safety.

Vaccines are generally foreign to the human body, and, like all medicines, there are a few people who are allergic to them. That's what we call "ballot of the demon" and has nothing to do with the safety of vaccines. The allergy rate of most vaccines is lower than one in a million, which is no higher than that for all medicines on average. Making an issue of these allergy victims is misleading people.

Vaccines remain the most effective weapon against contagious diseases, especially those caused by viruses. For bacterial diseases, we have antibiotics. But for the majority of viruses, there is no highly effective medicine and we must mainly rely on the human immune system to fight them. Vaccines are what we use to boost the human immune system.

－TAN QINDONG, A BEIJING-BASED DOCTOR