With a cure for coronavirus being top of mind these days, World Immunization Week comes at an appropriate time. Human life expectancy has greatly increased over generations due in part to the accessibility of vaccines to stem and even eradicate communicable diseases. In that sense, the search for a vaccine provides hope for preventing COVID-19 in years to come.
What Are Vaccines?
As witnessed with the novel coronavirus pandemic, germs can travel quickly through communities, making thousands—even millions—of people sick and killing many within a short period of time. Vaccines prevent disease from manifesting by encouraging people’s immune systems to fight off infections.
How Do Vaccines Work?
Vaccines are made up of germs, or pathogens, that at higher doses could cause the disease they are trying to prevent. The germs in a vaccine have been killed or extremely weakened so they do not make a person sick when introduced to the body. When a pathogen enters the body, it begins replicating in cells. When the body detects the pathogens within it, which have been inserted either orally, by injection, by puncture, through the skin, or through the nose, it:
1) stimulates the immune system by releasing antibodies to fight off the new germ it does not recognize,
2) destroys the invading germ, and
3) provides the immunity necessary for the person to not acquire the disease if exposed to it again, since it now recognizes the pathogen as dangerous and knows how to destroy it.
Why Are Vaccines Important?
Vaccines not only protect the inoculated from acquiring illness, they can protect an entire population, too. Community immunity, or herd immunity, occurs when enough people within a given population are vaccinated, thus preventing the germs from spreading among individuals. It also protects those in vulnerable populations, such as newborns and people with weak immune systems due to underlying illnesses, who are not able to be vaccinated or who have not built up sufficient immunity on their own.
What Vaccines Are Available Today?
Vaccines to prevent a multitude of once-crippling diseases are available today. The following is a list of illnesses vaccines prevent: 
• adenovirus
• anthrax
• cholera
• diphtheria
• hepatitis A
• hepatitis B
• hepatitis C
• Haemophilus influenza type b (Hib)
• human papillomavirus
• influenza
• Japanese encephalitis
• measles
• meningococcal
• mumps
• pertussis (whooping cough)
• pneumococcal
• polio
• rabies
• rotavirus
• rubella (German measles)
• shingles
• smallpox
• tetanus
• tuberculosis
• typhoid fever
• varicella (chicken pox)
• yellow fever
What Vaccines Are Currently in Development?
The World Health Organization (WHO) is working on many vaccines to prevent diseases ravaging parts of the world. They include norovirus, universal influenza, dengue, enterovirus, group B streptococcus, herpes simplex virus, human immunodeficiency virus (HIV), staphylococcus aureas, and human hookworm disease, among others.
Dozens of companies and research institutions are racing to create a vaccine to prevent coronavirus disease. To that end, the National Institutes of Health (NIH) has begun a public-private partnership in collaboration with 16 pharmaceutical companies to accelerate development. Researchers hope to identify a vaccine within the next six months. Six candidates are currently in the clinical trial phase of development, which involves testing in humans. After proper evaluation, a vaccine may be available to the public in about 12 to 18 months.
Sources: Centers for Disease Control and Prevention, “Vaccines and Preventable Diseases: Vaccine Basics,” https://www.cdc.gov/vaccines/vpd/vpd-vac-basics.html and “List of Vaccines Used in United States,” https://www.cdc.gov/vaccines/vpd/vaccines-list.html; Scripps Research, “Scripps Research Scientists Tackle COVID-19 Coronavirus Pandemic from Many Angles,” https://www.scripps.edu/news-and-events/press-room/2020/20200318-covid19-scripps-research.html; Vaccines.gov, “Vaccines Protect You,” https://www.vaccines.gov/basics/work/prevention and “Vaccines Protect Your Community,” https://www.vaccines.gov/basics/work/protection; World Economic Forum, “Coronavirus Vaccine: How Soon Will We Have One?” https://www.weforum.org/agenda/2020/03/vaccine-covid-19-coronavirus-pandemic-healthcare/; World Health Organization, “Immunization, Vaccines, and Biologics: Vaccines and Diseases,” https://www.who.int/immunization/diseases/en/.
