Below is the script for my public health radio show on immunizations. You can listen to the half-hour immunization show here. You can listen to the most current and all previous shows at the archive for Just for the Health of It public health radio show.
Today, I want to talk about vaccine-preventable infectious diseases, and I want to make it exceedingly clear that immunization with vaccines is of profound benefit to the 300+ million people in the United States and to billions of people around the world. In fact, it is difficult to even imagine our world without vaccines. I dare say that a world without vaccinations would be a scary place, far scarier than any picture painted by so-called “Anti-vaxxers.”
What would our world look like without vaccines? Well, it wasn’t that long ago that we lived in a world without vaccines. Smallpox killed over 300 million people in the 20th century. Smallpox was eradicated by 1979. I graduated from high school in 1979 and I have never known anyone with smallpox. Smallpox was eradicated. ERADICATED! That means that we don’t even have to immunize against it anymore! I don’t have any tattoos, but I do have a cool scar on my left shoulder from my smallpox immunization as a kid in the 1960s. This scar seems to me to be a small price to pay for a world without smallpox. I’ll gladly wear this scar as a reminder of the power of public health and vaccines. For those of you who have never had to live in a world with smallpox, I’ll explain the reason for the scar. The smallpox vaccine was not given with a hypodermic needle. It was not a shot, like many vaccinations. The vaccine was given using a two-pronged needle that was dipped into the vaccine solution. When removed, the needle retained a droplet of the vaccine. The needle is then used to prick the skin 15 times in a few seconds. As the body develops a response to the vaccine, a scar is eventually formed.
If one devastating disease eliminated isn’t enough, how about a second – Polio. Polio paralyzed or killed more than 500 million people in the 20th century. Polio was eradicated from the Western hemisphere by 1988. Just 30 years ago, the poliovirus was widespread across 125 countries, causing millions to endure lifelong paralysis. Last year there were poliovirus infections in just two countries – Afghanistan and Pakistan – with only 33 confirmed cases reported worldwide.
Today, our reawakening awareness of vaccine-preventable diseases not being prevented is due to the current measles outbreaks affecting 22 states. Measles was declared eradicated from the United States in 2000. Unfortunately, occasional measles cases acquired during international travel have found a foothold in locales with lower immunization rates. Borders don’t stop measles, vaccination does. Back in 1963, at the time the measles vaccine was introduced, measles killed approximately 2.6 million deaths every year. Today it has been reduced to 110,000 – that’s a 95% reduction. I’ll talk a little more about the current measles outbreaks a little later in the show.
The bottom line: Overall, worldwide, vaccines continue to prevent an estimated 2 to 3 million deaths every year.
More recently, maternal and neonatal tetanus, an often fatal disease, has been eliminated in all but 13 countries because of vaccination of women before or during pregnancy. And promising results from nations that have introduced the human papillomavirus vaccine early, suggests that cervical cancer is set to decline.
Further, new vaccines are on the horizon to protect against some of our most dangerous known pathogens. The Ebola vaccine has already played a critical role in controlling the spread of the current outbreak in the Democratic Republic of the Congo. Plus, the world’s first ever malaria vaccine is being piloted in routine immunization programs starting this month in three African countries.
I’d like to back up just a bit and review some of the currently available vaccines, which include:
Cholera
Dengue
Diphtheria
Hepatitis A
Hepatitis B
Hepatitis E
Human papillomavirus (HPV)
Influenza, or the flu
Several forms of encephalitis
Malaria
Measles
Meningitis
Mumps
Pertussis, or whooping cough
Pneumococcal disease, or pneumonia
Polio
Rabies
Rotavirus
Rubella
Tetanus
Tuberculosis
Typhoid
Varicella, or “chickenpox”
Yellow Fever
A couple of dozen other vaccines are in the pipeline.
For those of you unfamiliar with some of these diseases, you may want to thank the wonders of vaccines and the anonymity of prevention. One of the inherent problems of public health is the anonymity of prevention. When you prevent something from happening, people tend not to notice. We focus a lot more on things that do happen. This leads to an inevitable bias toward disease rather than disease prevention, sickness rather than health, and health care rather than public health.
So, I’ll highlight a few vaccine-preventable illnesses that may not capture much of our attention and often fly under the radar:
Cholera is an acute intestinal infection caused by ingestion of food or water contaminated with the Cholera bacterium. The annual burden of cholera has been estimated at 1.3 to 4.0 million cases and 21,000 to 143,000 deaths worldwide.
Dengue fever is from a mosquito-borne virus, with 40% of the world’s population at-risk.
Diphtheria is fatal in 5 – 10% of cases, with a higher mortality rate in young children.
Human papillomavirus (HPV) causes cervical cancer, which is the fourth most common cancer in women, with an estimated 266,000 deaths and 528,000 new cases worldwide in 2012.
Rotaviruses are the most common cause of severe diarrheal disease in young children throughout the world. About 215,000 children aged under 5 years die each year from vaccine-preventable rotavirus infections.
The reawakened interest in immunizations and infectious disease epidemics has been spurred on by the measles outbreaks occurring in the U.S. this year and continuing today. For those of you who may not have followed this story, here is a quick review:
[CDC measles story]
[Unvaccinated adult story]
Most of the people who avoid or delay vaccinations are best described as suffering from “Vaccine hesitancy.” A much smaller group of people would describe themselves as “Anti-vaxxers.” Vaccine hesitancy emerges from fear and doubt about vaccine safety or vaccine effectiveness, often from the prodding of “Anti-vaxxers.” The relatively small but growing number of Americans who are infected by “Vaccine hesitancy” are driving vaccination levels down enough to allow vaccine-preventable diseases to re-emerge in the United States. Ironically, the effectiveness of vaccines have been part of the downfall of immunization rates, as protection from a host of vaccine-preventable infectious diseases seems insignificant compared to worries about prevention somehow being worse than the disease. To me, this seems like an odd use of a privileged condition of living in a society largely free of diseases which were a scourge in the past.
So…I’m going to tell a story about polio, a scourge of the past, almost eradicated. I believe that this history will better inform our understanding of where we are today.
To tell this story, I am using material from Sciencehistory.org and Technologyreview.com
In the early 1950s, 25,000 to 50,000 new cases of polio occurred each year. Jonas Salk became a national hero when he allayed the fear of the dreaded disease with his polio vaccine, approved in 1955. Although it was the first polio vaccine, it was not to be the last; Albert Sabin introduced an oral vaccine in the United States in the early 1960s that replaced Salk’s. The disease was finally brought under control because of these vaccines,
In the first half of the 20th century, summer was a dreaded time for children. Although they could enjoy the long days of unfettered play, summer was also known as “polio season.” Children were among the most susceptible to paralytic poliomyelitis (also known as infantile paralysis), a disease that affects the central nervous system and can result in paralysis. When exposed to a poliovirus in the first months of life, infants usually manifested only mild symptoms because they were protected from paralysis by maternal antibodies still present in their bodies. However, as hygienic conditions improved and fewer newborns were exposed to the virus (which is present in human sewage), paralytic poliomyelitis began to appear in older children and adults who did not have an infant’s benefit of immunity. President Franklin Delano Roosevelt is perhaps the most famous victim of the poliovirus. In 1921, at the age of 39, he contracted the disease, one of the thousands that were afflicted that year.
Jonas Salk invented the polio vaccine in 1953 but never patented it. He believed that, like the sun, a vaccine for polio belonged to the people.
Salk tested the vaccine on himself and his own family first and later went on to work on a cure for AIDS. Salk is impressive, but he must be talked about along with Albert Sabin, who discovered a vaccine around the same time (and also didn’t patent it). Salk and Sabin’s vaccines are still used to prevent polio today.
Franklin D. Roosevelt (FDR) played a big role in funding and awareness. FDR had contracted polio in 1921. In 1938 as President he helped to found the (now titled) March of Dimes Foundation. By the late 40’s the foundation was raising tens of millions a year with the help of celebrities like Mickey Mouse. The March of Dimes Foundation funded Salk, and helped him to become the first one to find a vaccine for Polio.
Still, having a vaccine is not enough by itself to deal with the scourge of infectious disease. A vaccine needs to reach enough people across a broad swath of society to root our patterns of endemic infections and waves of epidemics.
In 1959, epidemiologists reported findings on the pattern of the disease. These suggested a shift in incidence according to age, geography, and race. By 1960, less than one-third of the population under 40 years of age had received the full course of three doses of the Salk vaccine plus a booster. Most of those who had were white and from the middle and upper economic classes. The disease raged on in urban areas among African Americans and Puerto Ricans and in certain rural locales among Native Americans and members of isolated religious groups.
The gap had to do with access to vaccination. Pediatricians were not well compensated. “This was the one thing they could do which was a guaranteed reasonable flow of cash.” The physicians resisted losing that cash; they argued for a vaccine that required their professional training.
The practice of medicine perverted by the profit motive is an age-old story. However, other pediatricians were more public health minded…
Beginning in January 1962, pediatricians in two Arizona counties, Maricopa and Pima, containing the state’s largest cities, Phoenix and Tucson, conducted separate but similar voluntary mass immunizations using Sabin’s vaccine. “Previous programs in the county, using the Salk vaccine, had failed to bring polio immunization to a satisfactory level,” they reported a year later in the Journal of the American Medical Association. The program was called SOS (Sabin Oral Sundays). More than 700,000 people were immunized – 75 percent of the total population in both counties. The vaccine was given at the cost of 25 cents, for those who could pay. It was given to population groups that were socially, racially, and culturally diverse, on Indian reservations and military posts and in urban and rural areas. The program became a model for subsequent U.S. mass-immunization programs. By the mid-1960s, Sabin’s vaccine was the only one in use in the United States. It was the Sabin vaccine that closed the immunity gap and effectively put an end to polio in the United States.
If the story of public health efforts to end polio does not give you some reasonable level of confidence in the profound value of vaccinations, perhaps I’ll share the story of smallpox eradication in another episode. Public health efforts are often far from perfect, yet the profound contribution that public health affords us, generation after generation, to this very day, is undeniable.
The bottom line: get vaccinated; get your children and grandchildren vaccinated; support your neighbors getting vaccinated. Together, we can defend ourselves and each other from a host of infectious diseases that still inhabit the planet.
Now, I’m going to switch gears a bit, and talk a bit about the many forms of conspiracy beliefs and scientific illiteracy that drives anti-vaccination efforts. First up, a more global perspective:
[Vaccinator shot in Pakistan story]
Next up, a little closer to home, the small, exploratory study that pointed to a potential link between the MMR vaccination and autism. You might call this the little study that wouldn’t die.
[Lancet retract Wakefield article]
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