At some point, almost every person in the United States is vaccinated. Though, many individuals want to know how vaccines are made, if they are effective, and whether or not they are safe. Public health professionals have a responsibility to provide accurate, understandable information and to handle vaccine safety concerns appropriately — and many answers lie in the history behind vaccinations and immunizations. The following 15 interesting facts about polio, smallpox, measles, pertussis, anthrax and rabies vaccines offer some insight into the methods used in attempts to eradicate various diseases.
- Parents were scared of the polio epidemics that occurred each summer; they kept their children away from swimming pools and sent them to stay with relatives in the country. They waited for a vaccine, closely followed vaccine trials and sending dimes to the White House to help the cause. When the polio vaccine was licensed in 1955, the country celebrated and Jonas Salk, its inventor, became an overnight hero.
- From the early 1900s, researchers pursued two different kinds of polio vaccine. One used inactivated (killed) viruses. The other kind used live but attenuated, or weakened, virus. Jonas Salk was the leading proponent of the killed virus and Albert Sabin became the foremost proponent of the attenuated virus approach.
- Evidence exists that the Chinese employed smallpox inoculation (or variolation, as such use of smallpox material was called) as early as 1000 CE. It was practiced in Africa and Turkey as well, before it spread to Europe and the Americas. Edward Jenner’s innovations, begun with his successful 1796 use of cowpox material to create immunity to smallpox, quickly made the practice widespread. His method underwent medical and technological changes over the next 200 years, and eventually resulted in the eradication of smallpox.
- Edward Jenner’s discovery relied extensively on knowledge of the local customs of farming communities and the awareness that milkmaids infected with cowpox, visible as pustules on the hand or forearm, were immune to subsequent outbreaks of smallpox that periodically swept through the area. As a learned man immersed in the secular and rational doctrines of the Enlightenment, Jenner applied the scientific methods of observation and experimentation to this parochial wisdom, ultimately conducting one of the world’s first clinical trials.
- Prior to 1963, almost everyone got measles; each year in the United States, there were approximately three to four million cases and an average of 450 deaths. Epidemic cycles occurred every two to three years. More than half the population had measles by the time they were six years old, and 90 percent had the disease by the time they were 15 years old. However, after the measles vaccine became available the number of measles cases dropped by 99 percent.
- In the United States, measles was targeted for elimination, and persisted at low incidence until 1989, when a measles epidemic swept the country. To prevent spread among school-age populations, a second dose of MMR (Measles-Mumps-Rubella) vaccine was recommended.
- In 1998, a study published by Andrew Wakefield suggested a relationship between the MMR vaccination and autism. Even though the Wakefield study was eventually retracted and the results were found to be faked, some parents still don’t like the idea of giving the MMR vaccine to their children. Although overall immunization rates in the U.S. are high, there are pockets of low immunization rates in some communities and at some schools that keep outbreaks going.
- Pertussis [PDF], or whooping cough, causes spasmodic, uncontrollable coughing that persists for weeks. Before the arrival of the vaccine, pertussis infected an average of 200,000 people a year in the United States alone. Although global rates have fallen significantly since the arrival of the vaccine, pertussis still kills almost 300,000 people every year.
- In 1996, the incidence of pertussis in Vermont (47.6 per 100,000) was higher than any other state (national incidence: 2.9 per 100,000). Vaccination rates in Vermont are among the highest in the United States; in 1996, 97 percent of children aged 19-35 months had received three or more doses of either diphtheria and tetanus toxoids (DT) or DTP (4). Because of the cyclical nature of pertussis outbreaks, however, periodic reemergence of pertussis epidemics can be anticipated. Even among highly vaccinated populations, waning immunity leads to a substantial population of susceptible older children and adults.
- The incidence of pertussis remains highest among young infants. In 2009, most (12 of 14) pertussis-related deaths reported to CDC were among infants aged younger than six months, who were too young to have received three doses of DTaP vaccine. As of 2009, the second highest incidence of pertussis is observed among school-aged children and adolescents, and the proportion of cases in this age group appears to be increasing.
- In the 1950s, after several government lab researchers died of anthrax, the government began working on an anthrax vaccine. The only anthrax vaccine available in the US today was licensed by the FDA in 1970 for human use by high risk individuals such as researchers, veterinarians, those working in the wool mill and livestock industries and others, who handle animals or animal products.
- The FDA licensed the current anthrax vaccine on the basis of its ability to prevent an anthrax infection among people prior to potential exposure. Because animal experiments demonstrated that spores can persist in the lungs for months before germinating and causing a serious infection, the vaccine is now being made available to people who have already been exposed. The goal is to provide additional protection to people already exposed in order to minimize their chances of developing an infection over time.
- Current anti-rabies vaccines are not prepared in the way that Pasteur used. Human Diploid Cell Vaccine (HDCV) is made in tissue culture using normal human WI-38 fibroblasts. The rabies virus is purified by passage through a filter and inactivated by beta-propriolactone. This inactivated virus vaccine is used almost exclusively in the developed world for pre- and post-vaccination of rabies. When used properly, HDCV can confer 100 percent protection.
- In September 1999, the USDA determined that all rabies vaccines currently approved for dogs should also be approved for wolves and wolfdogs. Their approval would be stated by an amendment to the Code of Federal Regulations, Title 9 (CFR9) declaring all vaccines approved for any member of the species Canis lupus. This can be seen at (Docket No. 99-040-1) Published APHIS Rules & Notices.
- It is strongly recommended that individuals at high recreational or occupational risk be vaccinated for rabies prevention. Individuals in professions of greatest risk are taxidermists, wildlife biologists, and professional or recreational trappers, especially those individuals traveling to Third World countries, where frequently infected domesticated animals are seen. The CDC recommends vaccination if traveling in Third World countries for longer than 30 days.