The near eradication of diseases such as polio and smallpox are obvious benefits, as are the prevention of the flu and other lethal viral diseases. The complications that results from some diseases such as the flu can be prevented with vaccines. Generally, the more people are vaccinated against a disease, the less likely that disease will infect members of that population.
If you travel to foreign countries, you still have to sure that you’re vaccinated against many diseases. Vaccination rates against measles are below 80% in much of Africa and India. Europe has seen new outbreaks, because vaccination rates dipped after the combined MMR vaccine (measles, mumps and rubella) was falsely linked to autism.
Polio vaccination has reduced worldwide incidence by 99%. But the disease continues to be detected in Pakistan, India, Afghanistan and Nigeria. So we need country-specific vaccines if we want to keep being protected from many diseases.
Vaccines do have risks, such as rashes, injection site tenderness, and fever-associated seizures called febrile convulsions and infections in those with compromised immune systems. But pre-screening of patients before vaccinations can help lower these risks. A doctor wouldn’t vaccinate you against the flu if you are currently sick or fighting another infection.
Modern vaccines are purer and safer than their older counterparts. Most developed countries use the inactivated polio vaccine and stopped using whole-cell pertussis (whooping cough) vaccines, which cause high rates of arm swelling, febrile convulsions and periods of unresponsiveness.
Clinical trials are conducted before a vaccine is made available. Postlicensure studies are conducted after a vaccine is approved by the FDA and used by the public. Surveillance programs for side effects continue to monitor a vaccine’s safety.
Surveillance efforts have been effective for a variety of vaccines. In 2007, Nicola Klein, co-director of the Kaiser Permanente Vaccine Study Center in Oakland, California, found that children aged between 12 and 23 months who had been immunized with a combination MMRV vaccine (for measles, mumps, rubella and varicella) had more febrile convulsions after vaccination than those who received separate MMR and varicella vaccines. The US immunization advisory committee withdrew its preference for the MMRV vaccine. A subsequent study showed that the combined vaccine resulted in one more febrile convulsion per 2,300 doses than the MMR and varicella vaccines given separately, prompting the majority of physicians to not recommend MMRV to a healthy 12-15-month-old child.
There is global and local monitoring and reporting of vaccine side effects, and this leads to safer vaccines, and less side effects. Scientists are studying how children with mitochondrial disorders respond to vaccines and natural infections. If vaccines pose a risk, doctors could take countermeasures against possible effects, for example by making sure the child is well nourished after immunization.
By monitoring patients’ pre-vaccination health status, asking where they will travel, and modifying vaccine administration protocols (such as the MMR and varicella vaccines), vaccinations will protect you and your loved ones from lethal diseases, and will cause less side effects.