Last week was bad for infectious diseases in Wisconsin. Measles and mumps, diseases seemingly reduced to only a memory in the United States by the introduction of vaccines, suddenly began making headlines once again.
By Thursday, the state health department confirmed four cases of measles in the Milwaukee area, leading hundreds to seek the measles vaccine at free clinics throughout the city over the weekend.
Scientists also published a study in the New England Journal of Medicine (NEJM) Thursday, showing the resurgence in the number of mumps cases reported in the United States in recent years, particularly among 18- to 24-year-old college students living in the Midwest.
Although the measles outbreak in Milwaukee and the resurgence of mumps across the country are separate issues, James Conway, a UW-Madison associate professor of pediatrics, said both cases highlight a growing concern in the medical community that a rising number of children in the United States are not receiving their recommended vaccines.
An unhealthy movement
It's a growing trend for parents not to immunize [their children] because they haven't seen the devastating effects of these diseases the way [older generations] did,"" said Craig Roberts, a University Health Services epidemiologist.
According to Conway, measles are a much more dangerous and contagious disease than mumps. Measles, commonly characterized by a body rash, can cause brain damage and death in severe cases, while mumps often cause swelling of the glands running along the jawline, according to the Centers for Disease Control and Prevention. Mumps are rarely deadly, but complications can include sterility and deafness.
Stephanie Marquis, spokesperson for the Wisconsin Department of Health and Family Services, said the state and local health departments are doing all they can to contain the measles outbreak in Milwaukee, but expects the number of measles cases in the state to grow.
""Measles can transfer easily and rapidly through the air,"" Marquis said. ""People don't know they have [measles] until the rash appears eight to 10 days after [infection].""
Vaccine laws and waivers
In 1982, Wisconsin began requiring children to receive one dose of the MMR vaccine, an immunization cocktail offering protection against measles, mumps and rubella. Several mumps outbreaks in the late-1980s led the state to begin requiring that children receive a two-dose MMR regimen, starting in 1990.
Today, doctors recommend children to receive the MMR vaccine between the ages of 12 and 15 months, and four and six years. According to Conway, the two-shot regimen is 99 percent effective against measles and 95 percent effective against mumps.
In Wisconsin, parents can refuse to have children immunized by filing a medical, religious or personal conviction waiver. A 2004 study in the Wisconsin Medical Journal showed that while the filing of medical and religious waivers in the state remained constant between 1990 through 2003, the number of parents filing personal conviction waivers steadily increased.
Conway said he suspects the growing number of parents choosing not to vaccinate is a combination of people ""losing sight of the disease"" and the vocal anti-vaccine movement, which argues vaccines are to blame for the rise in the numbers of autism cases in the United States.
More harm than good?
A 1998 Lancet paper by U.K. scientists fueled the anti-vaccine movement after it suggested the existence of a connection between MMR and autism. However, efforts to repeat the U.K. study and numerous studies since have led the CDC and the majority of the scientific community to acknowledge that there is no scientific link between MMR and autism.
""The connection between autism and vaccines has been studied to death and there is no cause-and-effect relationship between [them],"" Roberts said.
Yet, the announcement by the CDC last Friday that it would work with vaccine critics to explore vaccine safety issues shows the government is open to additional studies to examine whether or not the relationship between autism and vaccines exists.
Conway said the dip in the percentage of the population receiving vaccines in the United Kingdom has had no effect on the rates of autism in the country. Instead, the country's low vaccine rate of only 70 percent of the population has led to numerous outbreaks of measles and mumps.
""People forget about diseases and begin paying attention to rumors about vaccines,"" Conway said. ""It is a disservice to the community for a person to say 'I'm not going to vaccinate my kids. As long as everyone else vaccinates their kids, my kid will be fine.' If 10 to 20 percent of parents think the same way, then boom, outbreak.""
According to Conway, when vaccination rates fall below 80 percent of the population, ""an outbreak is waiting to happen,"" and the decrease in population vaccine rates appears to be rippling across the Atlantic Ocean.
Closer to home
While the recent measles outbreak in the Milwaukee area occurred in people who did not receive the MMR vaccine, the resurgence of mumps occurred in those who had previously received the required two-dose regimen.
The NEJM authors speculate that those who received the two-dose regimen of the MMR vaccine are losing immunity to mumps over time.
Marquis said the loss of immunity to mumps in combination with people living in close proximity on college campuses may be to blame for the higher mumps resurgence rates among college students compared to rest of the public.
""We always suspected the need for a better mumps vaccine,"" Conway said, pointing to the mumps outbreaks of the late-1980s that led to the country to shift to a two-dose MMR regimen. The NEJM report may now force doctors to re-evaluate the ability of the two-dose regimen to protect against mumps throughout one's lifetime.
""So many people protect kids by buckling their seatbelts in a car and giving them helmets when they bike. You don't know what day they'll be in an accident, but you do it anyway,"" Conway said. ""A vaccine is the same. You can't choose the day a disease is going to be introduced into the community. You can't just only vaccinate if there's an outbreak.
