What do you mean by safe? If your definition of the word safe is “harmless,” no vaccine or drug is 100 percent safe. Almost all vaccines can cause pain, swelling, or redness at the site of injection. With this definition of safe, almost nothing is safe. Even everyday activities contain hidden dangers.
For example, eating a piece of food or drinking anything liquid can block the throat and make you choke. Taking a bath or shower is not harmless. In fact in Japan, about 19,000 people die in their own bathrooms every year and over 5,000 people in the United States are killed when food lodges in their windpipe. Of the 5,051 people who died from choking in 2015, 2,848 were older than 74.
Food is often responsible for choking incidents in the elderly. But none of us consider taking a bath or eating solid food as unsafe activities. We continue to do them because the benefits of the activity outweigh the risks.
The second definition of the word safe is “having been preserved or protected from a real harm or real danger.” As of November 30, there have been over 63 million COVID-19 cases and 1,463,000 deaths. Unless you are a hermit living under a rock, you already know that COVID-19 is a real danger.
If we want to be back to some sort of “normality” where we can travel, meet our family and friends, and do the things we used to do before the pandemic, we need vaccines. Vaccines are, along with public health measures – washing hands, wearing a mask, physical distancing – are crucial to get in control of this virus. Without vaccines, we will be in this pandemic for several years to come.
Vaccine studies are performed by people who have the right expertise, knowledge, and experience. Vaccines safety trials begin in the lab, with tests and research on cells and animals, before moving on to human studies. The principle is to start small and only ever move on to the next stage of testing if there are no safety concerns.
After the pre-clinical stage, the vaccine is tested in humans (clinical trials). Clinical development is a three-phase process.
During Phase 1, small groups of people receive the trial vaccine. In Phase 2, the clinical study is expanded and the vaccine is given to people who have characteristics (i.e. age, physical health) similar to those for whom the new vaccine is intended. In Phase 3, the vaccine is given to tens of thousands of people and tested for efficacy and safety.
Each country has regulatory bodies that oversee vaccine safety and efficacy before they are used. Globally, the World Health Organization (WHO) coordinates a number of independent technical bodies that review the safety of vaccines prior to and even after they have been introduced. Vaccines that are approved for use by the WHO have gone through rigorous tests and clinical trials to show that they are safe and effective in controlling diseases. Evaluation of vaccines does not stop after approval.
Vaccines continue to undergo Phase 4 (post-approval) studies after the vaccine is licensed and used. Even though COVID-19 vaccines are being developed as rapidly as possible, they can only receive regulatory approvals if they meet stringent safety and efficacy standards.
So instead of only asking “will the coronavirus vaccine be safe”, we should also ask ourselves, do we want the pandemic to end? Do we want to risk getting COVID-19? Do we want to risk getting our high-risk (elderly or those with chronic medical conditions) friends and family members getting COVID-19?*
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Dr. Melvin Sanicas (@Vaccinologist) is a physician-scientist specializing in vaccines, infectious diseases, and global health.