Varicella zoster

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. More

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. More

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.) More