Studies Provide Evidence of Vaccine Safety And Efficacy
Oct 11, 2013

There are a lot of reasons why I love vaccines, but most importantly it’s because they save lives.  However, my appreciation of vaccines has also helped to elevate my appreciation of science.  This week has been another perfect example.  News coverage of several recent studies out this week help to illustrate the benefit of vaccines and provide further evidence of their efficacy.
Reduction in Pneumococcal Disease
At a IDWeek conference meeting earlier this week, researchers presented preliminary data and conclusions from a soon-to-be published study regarding the efficacy of the 13-valent pneumococcal conjugate vaccine.   MedPage Today covered the conference and reported that rapid uptake of the vaccine led to substantial reductions in invasive and noninvasive pneumococcus-related outcomes across all age groups after only 2 years.  Vaccination was tied to a 59% reduction in invasive pneumococcal disease-related hospitalizations in children younger than 5 years old, and a 25% reduction in related hospitalizations in adults.
The FDA approved the 13-valent version of the pneumococcal conjugate vaccine for use in pediatric patients 6 months to 5 years old back in 2010.  The new vaccine replaced a seven-valent version of the vaccine by adding protection against six additional strains of bacteria which accounted for 62% of cases of invasive pneumococcal disease not covered by the previous vaccine.
The study pointed to the “substantial herd immunity that was achieved,” by pointing to the 90% reduction of total invasive pneumococcal disease that occurred in older children and adults who were not immunized.  In other words, community immunity is even helping to protect those who are not vaccinated.

Image of unvaccinated child with varicella lesions in various stages.  (Photo courtesy of the American Academy of Pediatrics)

Image of unvaccinated child with varicella lesions in various stages. (Photo courtesy of the American Academy of Pediatrics)

Dramatic Decline in Incidence of Chicken Pox
Another development we’ve seen in regards to vaccine efficacy relates to the implementation of a two-dose varicella vaccination program which began in 2006.  According to study findings published in Pediatrics this week, the incidence of varicella (also know as chicken pox) has decreased across all age groups since the double dose vaccination program took effect.  Additionally, hospitalizations have declined by more than 40% during 2006 to 2010 compared with 2002 to 2005, and more than 85% compared with 1995 to 1998.  
Researchers suggested that high levels of immunity in the population have contributed to an overall decline of varicella disease observed in infants are who are not eligible for varicella vaccination, adults with low vaccination levels and immunocompromised individuals who are medically unable to receive this vaccine.  Once again, community immunity is in play.
No Serious Adverse Effects Linked to HPV Vaccine
News Medical reported on the safety of the quadrivalent HPV vaccine after researchers at Karolinska Institutet in Sweden released the details of their recent study in BMJ.  Researchers used patient data registries to monitor almost a million Swedish and Danish girls born between 1988 and 2000, and compared roughly 300,000 girls who had been HPV vaccinated with 700,000 who had not.  The researchers then used the data to study the incidence of any serious adverse effects of the vaccine, to include 53 different diagnoses requiring hospital or specialist care, including blood clots, neurological diseases, and autoimmune diseases such as type 1 diabetes. They found that none of these diseases were more common in the vaccinated girls relative to their unvaccinated peers.

Researchers concluded that “this population based cohort analysis provides strong evidence that autoimmune conditions, neurological diseases, and thromboembolic disease are not triggered by quadrivalent HPV vaccination”.

Too often, critics claim that vaccines are not well tested and that studies of safety and efficacy do not exist.  These dangerously inaccurate statements can easily be refuted with references to studies like those detailed above.

Since the average person may not have the time or inclination to follow immunization news as closely as we do here on Shot of Prevention, we will continue to highlight important studies in blog posts, in Facebook status updates, or through our @ShotofPrev Twitter feed.  Please “Like” our Vaccinate Your Baby Facebook page, follow us on Twitter and subscribe to this blog so that you can stay informed about the scientific studies that pertain to our ongoing investigation of our current immunization policies and practices.

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