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History of Vaccines Blog
The herpes zoster vaccine commercially available in the United States (Zostavax, Merck, generic zoster vaccine live) is 51% effective at preventing shingles in adults ages 60 and older, but it is less effective for older adults. For those over age 70, it is only 38% effective at preventing disease. Vaccine maker GSK hoped to produce a vaccine that worked better for older adults and that could be used by people with immunosuppressive conditions. (The licensed zoster vaccine is a live, attenuated virus vaccine and so is contraindicated in people with suppressed immune systems.)
How is the immune system similar to your marathon time? As we age, our immune response decreases at the same slope that our marathon race times increase. Presenters laid out this and some of the other problems of immunizing adults in the Symposium on Adult Immunizations, an early session at the Infectious Diseases Society 2014 conference at the Philadelphia Convention Center. Kenneth Schmader, MD, noted that though adults age differently – some adults at age 75 may be running marathons while others may be frail – all are subject to immune system senescence, and all are vulnerable to rapid functional declines that may result from an acute stressor, whether it’s a fall or a debilitating case pneumococcal pneumonia.
April 30, 2012
Varicella, or chickenpox, used to be a common childhood infection. Today’s grandparents and most parents can describe vividly what it was like to have chickenpox or to care for a child with this viral illness. Since the broad use of varicella vaccine, the number of cases in the United States has dropped dramatically. Even infants under the age of 6 months who are too young to get the vaccine have had a 90% drop in their rate of chickenpox since the introduction and widespread use of varicella vaccine. But chickenpox has not completely disappeared.
Philadelphia, Pennsylvania, is a city that requires evidence of varicella immunization to attend school (with certain exceptions) and maintains a vigorous surveillance of students attending school to see who has developed chickenpox. This tracking allows public health authorities to see the pattern of spread of chickenpox. A study published in the May 1 edition of the Journal of Infectious Diseases examined varicella cases over a 7-year period, during which about 2300 cases of varicella were seen in Philadelphia public school students.
Two important vaccine meetings were held September 11 and 12 at The College of Physicians of Philadelphia. The September 12 meeting entitled Research Integrity Challenges in Vaccine Development and Distribution for Public Health Emergencies was sponsored by the Department of Health and Human Services, the Office of Research Integrity, Drexel University, University of Pennsylvania Center for Bioethics, and The College of Physicians of Philadelphia. Speakers focused on vaccine development and distribution for biological threats and how the emergency preparedness experiences with A/H1N1 provided lessons that might inform future preparation for similar public health emergencies.
Most people view chickenpox as a disease of childhood–or, as the vaccine against it is increasingly used, as a disease of the past. But varicella zoster, the herpes virus that causes chickenpox, is sneaky. Even after a varicella infection clears, the virus hides in the nerve cells, inactive. In about 20% of people who have had chickenpox, the virus will reappear later in life to cause shingles, a disease of severe pain and blisters on the body or face. Blisters on the face can cause problems with vision and hearing, while the spread of the disease to the body’s internal organs can cause serious damage, including encephalitis (inflammation in the brain).
A vaccine against shingles was approved by the U.S. Food and Drug Administration in 2006 after it was shown to be effective (in clinical trials, the vaccine reduced the risk of shingles by 50%). Recently, a long-term follow-up study of 38,000 participants from the trial that led to its approval also demonstrated its long-term safety. (The study, from the Annals of Internal Medicine, can be found here.)
The use of the vaccine, however, does not reflect the data on its safety or effectiveness: a separate study, also in the Annals of Internal Medicine, indicated that despite the vaccine being available since 2006 and recommended since 2008 by the Advisory Committee on Immunization Practices for all adults 60 or older, early use of the vaccine has been between only 2% and 7% in the United States. (That study can be found here.)