While a somewhat controversial topic in some circles, vaccines have saved millions of lives and prevented countless infectious diseases from overwhelming the population for many, many years. Our world would be a very different place without vaccines and the efforts to develop them and use them to control and prevent disease around the world.
Here’s how vaccines have changed medicine over the years and continue to protect individuals and society today.
How Did Modern-Day Vaccines Start?
The smallpox vaccine, developed in 1796 by Edward Jenner, was the first successful vaccine. Jenner noticed that people who had previously been sick with cowpox did not get sick with smallpox. He later demonstrated that injecting a small amount of the vaccinia virus provided protection from being infected by the variola virus, the virus that causes smallpox in humans.
In 1961, the bifurcated needle was developed to help administer vaccinations more readily and at a lower price point. The needle’s prong-like design meant that it only needed a smaller portion of the vaccine and was simpler to use than previous methods.
This needle was pivotal to the success of the smallpox global eradication effort from 1966 to 1977, led by the World Health Organization (WHO). The campaign focused on achieving mass vaccination (at least 80% coverage in each country), followed by case-finding and ring vaccination of all known and possible carriers.
This successfully sealed the epidemic from the rest of the population and fully eradicated the disease. But even with the success of the eradication efforts, there’s still a possibility smallpox can make a comeback. For that reason, WHO maintains an emergency reserve of smallpox vaccinations in the event of another outbreak.
How Do Vaccines Help Control Disease?
Vaccinations protect us in a variety of different ways. They greatly reduce the impact of infectious diseases by controlling and preventing their spread, letting the field of medicine focus on other diseases and issues. There are a few major ways that vaccines help out our society.
As seen in the smallpox eradication campaign, vaccinations can fully eliminate the diseases they protect against. If nobody becomes infected in the first place, it can’t spread. Once a disease has been eradicated, it won’t re-emerge without human action or an environmental reservoir.
While global eradication of disease is the ultimate goal of immunization, only smallpox has been fully eradicated so far. Polio is the next disease targeted for eradication. One type of poliovirus has been eliminated globally, although the other two types still persist.
Although smallpox is so far the only total success case, the success of these efforts suggests that other infectious diseases can also be eradicated around the world — as long as there’s an effective vaccine, appropriate diagnostic tests, and high levels of herd immunity with sufficient surveillance.
When no cases of a pathogen are found in a given region, the disease is considered as eliminated in that area. While only smallpox has been fully eradicated, a greater number of diseases have been eliminated at the local level.
For example, measles has been eliminated from the Americas, while measles, mumps, and rubella (MMR) have been eliminated from Finland. Elimination is one step closer to full eradication, and elimination in one region is an encouraging sign that eradication is possible.
But local elimination doesn’t completely protect against the danger of re-introduction. There have been cases where a disease was eliminated locally and later re-introduced to the population from a region that still had outbreaks.
Then there are diseases that have an environmental or animal reservoir, such as tetanus or rabies. Diseases like these might never fully be eradicated because humans just can’t fully control those sources. But continued vaccination can help these diseases to eventually be eliminated at both the local and global levels.
Prevention and Control of Mortality, Morbidity, and Complications
If you get a vaccine before you’re exposed, it can be very effective in immunizing you against several diseases. Certain vaccines (including rabies, hepatitis B and A, measles, and varicella) can also protect you after an exposure. But even when a vaccine doesn’t successfully prevent a disease, the disease is typically milder if you’ve gotten the vaccine versus those who didn’t.
Many vaccines are given during childhood. You may even remember getting routine vaccines during your primary school years. Even for healthy children, their bodies and immune systems may not be strong or developed enough to effectively fight against disease without the help of immunization.
Overall, vaccines are estimated to prevent almost 6 million deaths worldwide each year. Vaccination not only leads to a significant decrease in incidence but a similar decrease in mortality and disease-related complications.
Complications can often have a greater long-term impact on those who get the disease than the disease itself. In some cases like polio, the impact can result in permanent physical damage, which are huge burdens on patients and can be major issues for medical systems.
Vaccination not only protects those who get the vaccines, but it also protects those who can’t. Some people have health conditions that prevent them from getting vaccinated.
These individuals can be protected from the disease through “herd protection” or “herd immunity,” which happens when a sufficient portion of the general population is immune to the disease.
Vaccines help to promote herd immunity by slowing the rate of transmission. Immunized individuals spread fewer pathogens for a shorter duration. This means that fewer people become infected, or if they do get infected, they get milder infections and can be contagious for less time.
Health Benefits of Vaccines
In addition to immunization of the targeted disease, vaccines also come with a host of other health benefits. In many cases, vaccinations can protect against related diseases.
For example, measle vaccinations also protect against related complications, including dysentery and bacterial pneumonia. And Hepatitis B vaccinations have been shown to reduce rates of liver cancer.
In certain cases, vaccines can protect against seemingly unrelated diseases, such as how flu vaccines reduce rates of mortality and cardiovascular or cerebrovascular diseases in elderly Americans. This, in turn, increases the average life expectancy.
As more people are immune to a disease, the need for antibiotics is also reduced. This can slow down the development of antibiotic-resistant strains that comes from overuse and over-prescription of antibiotics.
The public health benefits of vaccinations can’t be understated. Vaccination programs help improve primary health care services in developing countries, protect against potential bioterrorism, promote economic growth, and enhance equity for disadvantaged populations.
Responding to Public Health Emergencies
Vaccination plays a critical role in reducing (or potentially eliminating) the spread of infectious diseases. And amid a global pandemic, like the COVID-19 coronavirus pandemic, vaccines may be the only way to fight against it.
The biopharmaceutical industry is uniquely qualified to respond to public health emergencies. Biopharmaceutical companies are hard at work conducting research and development for vaccines, as well as providing manufacturing support.
While this process can take years from start to finish, companies are making efforts to significantly shorten the timeline to fight against COVID-19.
Previous vaccination efforts, meant to reduce the spread of and even eliminate diseases, have historically been successful. While it’s not available yet, a coronavirus vaccine may signify hope for a “return to normal.”