We share more than food and culture within our homes and communities. We can also spread disease. Luckily, we live in a time when vaccines can protect us from many of the most serious illnesses. Staying current on your shots helps you—and your neighbors—avoid getting and spreading disease.
Vaccines have led to large reductions in illness and death—for both kids and adults—compared with the pre-vaccine era, says Dr. David M. Koelle, a vaccine expert at the University of Washington in Seattle. Vaccines will prevent about 322 million illnesses, 21 million hospitalizations, and 732,000 deaths among U.S. children born over the last 20 years, according to a recent report.
Vaccines harness your immune systems natural ability to detect and destroy disease-causing germs and then remember the best way to fight these germs in the future. Vaccination, or immunization, has completely eliminated naturally occurring smallpox worldwide—to the point that we no longer need to get shots against this fast-spreading, once-deadly disease. Polio too has been eliminated in the U.S. and most other nations as well, thanks to immunizations. Poliovirus can affect the brain and spinal cord, leaving people unable to move their arms or legs, or sometimes unable to breathe.
These childhood diseases used to be dreaded problems that would kill or paralyze children, says Koelle. In the 1950s, it was a common occurrence for kids to be fine in the spring, get polio over the summer, and then have to go back to school in the fall no longer able to walk.
Experts recommend that healthy children and teens get shots against 16 diseases (see Wise Choices box). With this growing list, many disabling or life-threatening illnesses have significantly declined in the U.S., including measles, rubella, and whooping cough. But, unlike smallpox, these disease-causing germs, or pathogens, still exist around the world.
These days, the risks of not being vaccinated in a developed country, like the United States, may seem superficially safe because of low rates of infection due to vaccination and other advances in public health, says Koelle. But we live in an era of international travel where we can be exposed to mobile pathogens. So even if you dont travel, a neighbor or classmate could go overseas and bring the disease back to your area.
When the rates of vaccination drop, there can be a resurgence of the disease, explains Dr. Saad Omer, a global health researcher at Emory University in Atlanta. For instance, measles was completely eliminated in the U.S. in 2000. But since then, hundreds of travel-related cases have occurred, with a spike of more than 600 measles cases in 2014.
Omer and colleagues examined U.S. reports on measles outbreaks since 2000. We found that measles cases have occurred mostly in those who are not vaccinated and in communities that have lower rates of vaccination. And thats true for many vaccine-preventable diseases, Omer says. Most of the unvaccinated cases were those who chose not to be vaccinated or not to have their children vaccinated for non-medical reasons.
When enough people are vaccinated, the entire community gains protection from the disease. This is called community immunity. It helps to stop the spread of disease and protects the most vulnerable: newborns, the elderly, and people fighting serious illnesses like cancer. During these times, your immune system is often too weak to fend off disease and may not be strong enough for vaccinations. Avoiding exposure becomes key to safeguarding your health.
Theres a huge benefit to all of us getting the recommended vaccines, explains Dr. Martha Alexander-Miller, an immune system expert at Wake Forest Baptist Medical Center in Winston-Salem, NC. Number one, vaccines protect you. But they also limit the presence of disease-causing entities that are circulating in the community. So, youre helping to protect individuals who may not be capable of protecting themselves, for example because they are too young to get vaccinated.
When expectant moms are vaccinated, immune protection can pass through the placenta to the fetus. Early on, the babys immune system is immature. So theres a period of vulnerability where disease and death can occur, Omer explains. But the mothers own antibodies—proteins formed by her immune system—can protect the baby.
Doctors recommend that moms-to-be get both flu and Tdap (tetanus, diphtheria, and whooping cough) shots, so her body will make antibodies against these diseases. A mothers antibodies can help protect the newborn until they can receive their own vaccinations.
Some vaccines must be given before pregnancy. Rubella, for instance, can cause life-altering birth defects or miscarriage if contracted during pregnancy. Theres no treatment, but the measles, mumps, and rubella (MMR) vaccine given pre-pregnancy offers prevention. Vaccines for many other common diseases that put newborns at risk are being studied.
Weve made amazing progress in the development of effective vaccines, says Alexander-Miller. Our ability to have such breakthroughs is the end result of very basic research that went on for years and years. But we still dont know everything that we need to know about how to create the very best vaccine. NIH-funded scientists are continuing to search for new ways to stimulate protection against various diseases.
Koelle studies how our bodies fight herpes viruses. There are 8 related herpes viruses, but the body responds differently to each one. So far, we only have a vaccine for one: varicella–zoster virus, which causes chickenpox and shingles.
Koelles team is comparing how our immune system responds to chickenpox and the herpes simplex viruses, which cause mouth and genital sores. Were hoping to harness the success that has been possible with the chickenpox vaccine and see if we can create a vaccine that would work for both chickenpox and shingles and also herpes simplex, he says.
Researchers are also working to improve existing vaccines. Some vaccines require a series of shots to trigger a strong immune response. The protection of other vaccines can fade over time, so booster shots may be needed. Some, like the flu vaccine, require a shot each year because the virus changes so that the vaccine no longer protects against new strains. So keeping up with the latest flu vaccines is important.
Ask your doctors office whether your vaccinations are current. You may also find records of vaccinations at your state health department or schools. If you cant find your records, ask your doctor if its OK to get a vaccine you might have received before.
It can be easy to take vaccines for granted, because youll never know all the times you wouldve gotten really sick had you not been vaccinated, says Alexander-Miller.
Help your community keep diseases at bay: Stay up-to-date with vaccines.
References Benefits from immunization during the vaccines for children program era – United States, 1994-2013. Whitney CG, Zhou F, Singleton J, Schuchat A; Centers for Disease Control and Prevention (CDC). MMWR Morb Mortal Wkly Rep. 2014 Apr 25;63(16):352-5. PMID: 24759657.
Association Between Vaccine Refusal and Vaccine-Preventable Diseases in the United States: A Review of Measles and Pertussis. Phadke VK, Bednarczyk RA, Salmon DA, Omer SB. JAMA. 2016 Mar 15;315(11):1149-58. doi: 10.1001/jama.2016.1353. Review. Erratum in: JAMA. 2016 May 17;315(19):2125. PMID: 26978210.
Extensive CD4 and CD8 T Cell Cross-Reactivity between Alphaherpesviruses. Jing L, Laing KJ, Dong L, Russell RM, et al. J Immunol. 2016 Mar 1;196(5):2205-18. doi: 10.4049/jimmunol.1502366. Epub 2016 Jan 25. PMID: 26810224.
NIH News in Health, July 2016