In this blog, I have spent an inordinate amount of time refuting claims from vaccine deniers about the effectiveness of vaccines (along with debunking claims about safety). Even if the safety claims were legitimate, and they are not, in general, even close to being legitimate, the antivaccinationists give disproportionate weight to the adverse events over the actual benefits of the vaccination. For example, I just reviewed an article about non-medical exemptions to vaccinations, in which the authors concluded that, “the past several decades have seen a shift in parental concerns from disease prevention to vaccination risks, largely and paradoxically because of the success of large scale immunization.”
But it’s much more than just ignoring the successes of vaccinations, sometimes the vaccine denier community will actually misrepresent and revise history, to make facetious, and easily discredited, claims such as diseases were disappearing before vaccines. Sometimes, the vaccine refusers confuse mortality and morbidity, failing to understand how vaccines have reduced both. Or they just invent stories to show that the decline in infectious diseases was caused by anything but vaccines.
In a recently published article in the high impact factor New England Journal of Medicine, the researchers investigated the change in rates of pneumonia-related hospitalizations since the introduction of the pneumococcal vaccine (PCV-7, the 7-valent vaccine). The PCV-7 vaccine has been replaced by the PCV-13 (for children) and PCV-23 (for adults), which provide better effectiveness against the disease. The complications of pneumonia are numerous:
- Most pneumococcal infections are mild. However some can be fatal or result in long-term problems, such as brain damage or hearing loss.
- Meningitis is the most severe type of invasive pneumococcal disease. Of children younger than 5 years old who get pneumococcal meningitis, about 1 out of 10 dies of the infection and others may have long-term problems, such as hearing loss or developmental delay. The chance of death increases among elderly patients.
- Bacteremia is also a type of invasive pneumococcal disease that infects the blood. About 4 out of 100 children with this blood stream infection die of it. The chance of death increases among elderly patients.
- Pneumonia is an infection of the lungs that can cause mild to severe illness in people of all ages. Complications of pneumococcal pneumonia include infection of the space between membranes that surround the lungs and chest cavity (empyema), inflammation of the sac surrounding the heart (pericarditis), and blockage of the airway that allows air into the lungs (endobronchial obstruction), with lung collapse (atelectasis) and collection of pus (abscess) in the lungs. About 5 out of 100 people with non-invasive pneumococcal pneumonia will die from it, but that rate may be higher among elderly patients.
- Sinus and ear infections are usually mild and are much more common than the more severe forms of pneumococcal disease. However, some children develop repeated ear infections and may need ear tubes.
The researchers examined the Nationwide Inpatient Sample database, which is the largest publicly available all-payer inpatient care database in the United States. It contains data from approximately 8 million hospital stays each year. This database allows researchers to mine for all kinds of information at both the macro and micro levels, and to uncover nationwide trends in medical outcomes.
The researchers compared the pneumonia-related hospitalization rate between 1997-1999 (before the PCV-7 vaccine was available) and 2007-2009 (well after the vaccine was available). The dramatic results were:
- From 1997 through 2009, there were 17,892,085 hospitalizations for pneumonia, representing 4.1% of all U.S. hospitalizations other than those for childbirth, including 7.2% of hospitalizations among children and 3.9% of hospitalizations among adults.
- The annual rate of hospitalization for pneumonia among children younger than 2 years of age declined by 551.1 per 100,000 children (95% confidence interval [CI], 445.1 to 657.1), which translates to 47,000 fewer hospitalizations annually than expected on the basis of the rates before PCV7 was introduced. This represents a 43.2% reduction in hospitalizations from pneumonia.
- The rate for adults 85 years of age or older declined by 1300.8 per 100,000 (95% CI, 984.0 to 1617.6), which translates to 73,000 fewer hospitalizations annually. This is a 22.8% reduction in hospitalizations
- For the three age groups of 18 to 39 years, 65 to 74 years, and 75 to 84 years, the annual rate of hospitalization for pneumonia declined by 8.4 per 100,000 (95% CI, 0.6 to 16.2), 85.3 per 100,000 (95% CI, 7.0 to 163.6), and 359.8 per 100,000 (95% CI, 199.6 to 520.0), respectively. Overall, we estimated an age-adjusted annual reduction of 54.8 per 100,000 (95% CI, 41.0 to 68.5), or 168,000 fewer hospitalizations for pneumonia annually.
- Although the researchers identified other factors that may have been responsible for the reduction of pneumonia (such as reduced smoking rates), previous observations have shown that the rate of pneumonia may actually increase when smoking drops (please don’t use that as evidence that smoking can improve your health, the study wasn’t powered to examine that question). They also eliminated increased flu vaccination as causing the decreased pneumonia rates, because the CDC did not recommend flu vaccines for children until the mid-2000’s.
The antivaccinationists will often point to better sanitation or improved medical care as the reasons for a decline in a vaccine preventable disease, rather than accepting the data that supports vaccines causing the decline. But unless there was a massive change in sanitation and/or healthcare practices in 1999, the only conclusion we can make is that the pneumococcal vaccine itself is both correlated and causal to the decrease in pneumonia hospitalization rates. Of course, I’ll await the logical fallacy from the vaccine deniers that will try to show that this is a result of something. Possibly bottled water? Global warming? GMO foods? Aliens?
Vaccines save lives, and we have more evidence supporting that fact.
- Blank, NR, Caplan AL, Constable C. Exempting Schoolchildren From Immunizations: States With Few Barriers Had Highest Rates Of Nonmedical Exemptions. Health Aff. July 2013; 32(7); 1282-1290. doi: 10.1377/hlthaff.2013.0239. PMID: 23836745. Impact factor: 4.641.
- Griffin MR, Zhu Y, Moore MR, Whitney CG, Grijalva CG. U.S. Hospitalizations for Pneumonia after a Decade of Pneumococcal Vaccination. N Engl J Med 2013;369:155-63. DOI: 10.1056/NEJMoa1209165. Impact factor: 51.658
- McCarthy NL, Weintraub E, Vellozzi C, Duffy J, Gee J, Donahue JG, Jackson ML, Lee GM, Glanz J, Baxter R, Lugg MM, Naleway A, Omer SB, Nakasato C, Vazquez-Benitez G, DeStefano F. Mortality Rates and Cause-of-Death Patterns in a Vaccinated Population. Am J Prev Med 2013;45(1):91–97. doi: 10.1016/j.amepre.2013.02.020. Impact factor: 3.945