What Are Whole-Virus Vaccines & Why Are They Controversial?
When it comes to vaccines, everyone seems to have a firm opinion. Most of the skepticism around vaccines is derived, in part, because of myths about vaccines you should stop believing, such as the idea that all vaccines carry the same level of risk.
Not all vaccines are created equal, and thus, they all behave differently within the body. Despite their differences, however, their ultimate goal is to train your body's defense system so it can protect you against numerous diseases (one of the easiest ways to boost your immunity).
Among the multiple types of vaccines, whole-virus vaccines are arguably the oldest and most widely used vaccine types. Believe it or not, according to a 2014 article in Proceedings of the National Academy of Sciences of the United States of America, they have been around since the late 18th century, when the smallpox vaccine was invented. However, there are records of early forms of vaccination being used in China over a thousand years prior.
Unlike vaccines that focus on exposing your immune system to only one or two viral components, whole-virus vaccines, as their name suggests, expose it to the entire virus. This can be achieved through two mechanisms: either by using live-attenuated vaccines or inactivated vaccines. The former uses a weakened form of the virus, allowing it to trigger an immune response without causing severe illness, while the latter relies on a killed virus that cannot cause disease.
Both have their pros and cons. Yet, many remain skeptical about them
One of the main strengths of live-attenuated vaccines is that they prepare your body to recognize the real virus better later, meaning that they create a more robust and longer-lasting immune response with fewer doses (just one or two). In contrast, despite also being effective, inactivated vaccines require more doses to achieve the same level of protection. On the flip side, by relying on a killed virus, inactivated vaccines offer more safety for vulnerable populations, such as newborns, pregnant people, the elderly, and those with some chronic health conditions.
Nevertheless, controversy arises when comparing whole-virus vaccines with modern alternatives such as messenger RNA (mRNA) vaccines. The truth about mRNA vaccines is that they work by telling your cells to make a harmless piece of a virus, usually a protein (antigen), so that your immune system learns to recognize and fight it when facing the real thing. They are also faster to produce, meaning that they can become more readily available when needed.
As Dr. James Campbell, vice chair of the American Academy of Pediatrics Committee on Infectious Diseases, explained (via NBC4 Washington), modern technologies allow for a more targeted approach with fewer health risks compared to whole-virus vaccines, even compared to inactivated ones in some cases. As a result, despite their proven efficacy, some experts argue that the role of whole-virus vaccines should be limited to specific diseases where they are most effective, while future efforts should pivot toward some of the newer vaccine types that offer broader benefits and fewer risks.