Vaccines

The History and Importance of Vaccines for Health

The history of vaccines is one of the most successful chapters in medical science. It began in the 18th century with Edward Jenner's groundbreaking work against smallpox, where he demonstrated that inoculation with cowpox could provide protection against the deadly disease. This laid the foundation for the concept of vaccination, which has since evolved into a cornerstone of global public health efforts. During the 20th century, the introduction of vaccines against diseases such as polio, measles, diphtheria, and whooping cough led to a dramatic reduction in child mortality and epidemics worldwide.

Vaccines not only protect individuals but also contribute to what is known as herd immunity, meaning that even unvaccinated people (who cannot be vaccinated for various reasons) receive indirect protection when a sufficiently large proportion of the population is immune. This is crucial for controlling infectious diseases and preventing outbreaks. A clear example of the importance of vaccines in our time is the COVID-19 pandemic, where the development and distribution of effective mRNA vaccines proved vital in reducing mortality, disease burden, and strain on healthcare. Vaccines became a tool to maintain societal functions and protect the most vulnerable groups. Vaccinations are now a cornerstone in both child healthcare and adult medicine, and are considered one of the most cost-effective interventions for improving global health.

“Vaccines are one of humanity's most important medical discoveries. At the same time, it is absolutely crucial that every new vaccine is thoroughly studied. In a clinical study, the health and well-being of the individual participant always come first. It is important that new vaccines are properly evaluated, so that the benefits clearly outweigh the risks for both the individual and society as a whole.”

Erik Rein-Hedin

MD, PhD candidate

Read about Erik Rein-Hedin here

Common Side Effects of Vaccines

Just like all medicines, vaccines can cause side effects, but these are usually mild and temporary. The most common reactions are soreness, redness, and swelling at the injection site, as well as fever, headache, fatigue, and muscle aches. Sometimes, flu-like symptoms may be experienced for a couple of days.

More serious side effects include allergic reactions, severe swelling, or febrile seizures. Myocarditis or pericarditis (inflammation of the heart muscle or sac), blood clots, and certain neurological diseases have also been linked to vaccines in rare cases. However, such serious side effects occur very infrequently. The development and approval of new vaccines take place under careful supervision through extensive clinical trials and ongoing follow-up after approval.

Why is it important to develop new vaccines?

Despite the successes of vaccines, there is still a great need for the development of new ones. Several infectious diseases currently lack effective vaccines, such as HIV, malaria, Lyme disease, and certain forms of meningococcal infections. Furthermore, access to existing vaccines is unevenly distributed across the world, leading to recurring outbreaks of diseases like measles and polio in low-income countries. New technologies, such as mRNA vaccines, have shown great potential but are not yet fully developed for widespread use against diseases other than COVID-19. There is also a need for vaccines that provide longer and better protection, require fewer doses, and are easier to handle, store, and use. Vaccine research is therefore crucial to address future pandemics, antibiotic resistance, and prevent infectious diseases.

CTC's experience with vaccine studies

CTC has conducted and participated in both larger and smaller vaccination studies in Sweden, often as part of large, global studies to develop new vaccines. One example is a study to develop a vaccine against Lyme disease – a disease for which there is currently no approved vaccine. Other examples of vaccine studies at CTC include vaccines against E. coli (an intestinal bacterium that can cause serious infections), RSV, and new formulations of influenza vaccines. For most vaccine studies, CTC seeks healthy volunteers, but some vaccine studies include different patient groups or individuals with risk factors for certain diseases.

Do you want to participate in studies at CTC?

When you register with our database, you will receive information about upcoming or ongoing studies that match your profile. Once you have expressed your interest in participating, our staff will contact you. Your participation is completely voluntary, and you can withdraw at any time.