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| Varicella vaccine has long-term effectiveness against chicken pox Posted: 31 Mar 2013 09:00 PM PDT Chicken pox, the childhood affliction of earlier generations, has been largely neutralized by the varicella vaccine, according to a new study by the Kaiser Permanente Vaccine Study Center, which appears in the current online issue of Pediatrics.
The 14-year study followed 7,585 children who were vaccinated in 1995, when they were 12 to 23 months old, to assess the long-term effectiveness of the vaccine and the impact on the epidemiology of varicella (chicken pox) and herpes zoster (shingles). Researchers also observed the impact of the second dose of varicella vaccine, introduced in 2006. The varicella vaccine was licensed in the United States in 1995, and recommended soon after by the Advisory Committee on Immunization Practices for routine administration to children. Prior to that, chicken pox was ubiquitous, with more than 90 percent of young people experiencing infection by the age of 20. Over the entire follow-up period, the incidence rate of chicken pox in this cohort was 9 to 10 times lower than corresponding rates in unvaccinated children of the same age in the pre-vaccine era. This resulted in an overall vaccine effectiveness rate of approximately 90 percent. “Clearly, the vaccine is a very effective tool in preventing or limiting the severity of chicken pox in young people,” said Randy Bergen, MD, chief of outpatient pediatrics at Kaiser Permanente’s Walnut Creek Medical Center and a pediatric infectious disease consultant. “As with any vaccine, though, the rate of vaccination has a huge impact on effectiveness. The more children vaccinated, the more effective the vaccine is for the entire community. At Kaiser Permanente, our use of a comprehensive electronic health record, KP HealthConnect, enables us to quickly identify children in the targeted age ranges who have not been vaccinated, and to reach out to their parents to ensure they get the shots. Keeping vaccination rates high confers benefit on the community as a whole because there are fewer children who can contract and spread the virus.” A total of 1,505 breakthrough cases of chicken pox were reported within the study cohort of 7,585 children in the 14 years following varicella vaccination. “Breakthough cases” are so named because they occur despite the child having received the varicella vaccine; the virus “breaks through” the defenses afforded by the vaccine. Cases were classified as “mild” (less than 50 lesions), “moderate” (51 to 300 lesions) and “severe” (more than 300 lesions). Very few cases were severe (only 28 of 7,585 children over 14 years), whereas in the pre-vaccine era most children experienced severe symptoms. Prevention of moderate to severe disease was achieved with one dose of varicella vaccine; no cases were reported after the second dose. The incidence rate of breakthrough varicella steadily decreased over time and no increase was observed during the 14 years of follow-up. The apparent increase in the vaccine’s effectiveness over time, according to lead author Roger Baxter, MD, co-director of the Kaiser Permanente Vaccine Study Center, “is likely the result of vaccine failure occurring early, while breakthroughs became rare due to high vaccine effectiveness both directly and through herd immunity.” The continuing decline in breakthrough rates observed in 2008 and 2009 may have been the result of the implementation of the second dose in 2006, researchers said. The second dose of varicella is typically given at ages 4 to 6 years. However, it could potentially be of more benefit if given early after the first dose ? if varicella is circulating ? by increasing protection for infants too young to receive the vaccine and immune-compromised children who cannot receive a live vaccine. The risk of herpes zoster, commonly known as shingles, was not increased in vaccinated children, and appeared to be lower in vaccinated children than in the pre-vaccine era. There were 46 confirmed cases of shingles among the cohort, suggesting an approximately 40 percent decreased incidence of herpes zoster in vaccinated children. ### Additional authors on the study include Paula Ray, MPH, Edwin Lewis, MPH, and Bruce Fireman, MA, with the Kaiser Permanente Vaccine Study Center; Patricia Saddier, MD, PhD, and Trung N. Tran, MD, PhD, of the epidemiology department, Merck Sharp & Dohme, Corp., Whitehouse Station, N.J.; Steve Black, MD, of the Center for Global Health, Cincinnati Children’s Hospital, Cincinnati; Henry R. Shinefield, MD, of the University of California San Francisco Medical Center; and Paul M. Coplan ScD, MBA, of Purdue Pharma, Stamford, Conn. Trung Nam Tran, MD, and Paul Coplan were employees of Merck Sharp & Dohme, Corp. at the time of the study. Patricia Saddier, MD, is currently still an employee of Merck Sharp & Dohme, Corp. Roger Baxter, MD, has received research grants from Merck, Sanofi Pasteur, GSK and Novartis. Steve Black, MD, is a consultant for Novartis, and is on data safety monitoring boards for Novartis, GSK and the World Health Organization. All other authors report no conflicts of interest. About the Kaiser Permanente Vaccine Study Center Founded in 1985, the Kaiser Permanente Vaccine Study Center began as a way of responding to numerous requests to use Kaiser Permanente’s large population for vaccine efficacy studies. Key studies have focused on Haemophilus influenza, type B (Hib), chickenpox, pneumococcus, rotavirus and flu vaccines. The center operates 31 sites in Northern California and collaborates with Kaiser Permanente’s Northwest, Hawaii and Colorado regions, as well as participates in several Centers for Disease Control and Prevention and National Institutes of Health studies. For more information, visit http://www.dor.kaiser.org/external/DORExternal/vsc/index.aspx. About the Kaiser Permanente Division of Research The Kaiser Permanente Division of Research conducts, publishes and disseminates epidemiologic and health services research to improve the health and medical care of Kaiser Permanente members and the society at large. It seeks to understand the determinants of illness and well-being and to improve the quality and cost-effectiveness of health care. Currently, DOR’s 600-plus staff is working on more than 250 epidemiological and health services research projects. For more information, visit http://www.dor.kaiser.org. About Kaiser Permanente Kaiser Permanente is committed to helping shape the future of health care. We are recognized as one of America’s leading health care providers and not-for-profit health plans. Founded in 1945, our mission is to provide high-quality, affordable health care services and to improve the health of our members and the communities we serve. We currently serve more than 9 million members in nine states and the District of Columbia. Care for members and patients is focused on their total health and guided by their personal physicians, specialists and team of caregivers. Our expert and caring medical teams are empowered and supported by industry-leading technology advances and tools for health promotion, disease prevention, state-of-the-art care delivery and world-class chronic disease management. Kaiser Permanente is dedicated to care innovations, clinical research, health education and the support of community health. For more information, go to: kp.org/newscenter. Contact: Catherine Hylas Saunders |
| New technique shows promise in restoring near vision without glasses Posted: 31 Mar 2013 09:00 PM PDT By middle age, most people have age-related declines in near vision (presbyopia) requiring bifocals or reading glasses. An emerging technique called hyperopic orthokeratology (OK) may provide a new alternative for restoring near vision without the need for glasses, according to a study, “Refractive Changes from Hyperopic Orthokeratology Monovision in Presbyopes“, appearing in the April issue of Optometry and Vision Science, official journal of the American Academy of Optometry. The journal is published by Lippincott Williams & Wilkins , a part of Wolters Kluwer Health.
For middle-aged patients with presbyopia, wearing OK contact lenses overnight can restore up-close vision in one eye, according to the study by Paul Gifford, PhD, FAAO, and Helen A Swarbrick, PhD, FAAO, of University of New South Wales, Sydney. “The authors have shown the feasibility of correcting one eye for near vision through OK, in which overnight contact lens wear shapes the cornea of one eye to allow in-focus near vision for reading,” comments Anthony Adams, OD, PhD, Editor-in-Chief of Optometry and Vision Science. Overnight OK Lens Wear Restores Near Vision in One Eye The study included 16 middle-aged patients (43 to 59 years) with age-related loss of near vision, or presbyopia. Presbyopia is caused by age-related loss of flexibility in the cornea?the transparent front part that lets light into the eye. Orthokeratology is a clinical technique to correct vision using specially designed rigid contact lenses to manipulate the shape of the cornea. Dr Adams likens OK therapy to orthodontic treatment using braces to change the alignment of the teeth. Drs Gifford and Swarbick evaluated a “monocular” technique, with patients wearing a custom-made OK lens in one eye overnight for one week. To preserve normal distance vision, the other eye was left untreated. In all patients, the monocular OK technique was successful in restoring near vision in the treated eye. The improvement was apparent on the first day after overnight OK lens wear, and increased further during the treatment week. Eye examination confirmed that the OK lenses altered the shape of the cornea, as they were designed to do. Nightly Lens Wear Needed to Retain Correction Vision in the untreated eye was unaffected, and all patients retained normal distance vision with that eye; essentially this gives the patient the dequivalent of ‘monovision’ that is usually done with contact lenses or surgery. To retain the correction in near vision, patients had to continue wearing their OK lenses every night. Dr Adams likens this ongoing treatment to the “retainer” that orthodontic patients have to wear nightly. As expected, when patients stopped wearing their OK lens after the treatment week, presbyopia rapidly returned. By about age 45 to 50, most people need bifocals or some other form of vision correction to restore vision for reading and other up-close tasks. Alternatives for presbyopia have been introduced, including fitting a contact lens for distance vision in one eye and a lens for near vision in the other eye. This is the so called monovision, now the authors show it can be achieved without the need to wear a contact lens during the day. “However, the chief problem with monovision for many people is that their stereoscopic 3D vision is degraded and many find that hard to tolerate,” according to Dr Adams. Although overnight OK is not a new technique, it has been mainly used to reduce nearsightedness (myopia) in younger patients. The new study shows that OK is similarly effective in changing corneal shape, and achieving desired correction in near vision, in older patients with presbyopia. The new study suggests that overnight OK lenses are a feasible alternative for correction of presbyopia, “sufficient to provide functional near vision correction white retaining good distance visual acuity,” Drs Gifford and Swarbick write. The technique is safe, with the cornea returning to its previous shape about a week after the patient stops wearing the lenses. “This study demonstrates that OK is quite viable as a nonsurgical option for monovision that does not require wearing contact lenses during the day, although it does require ‘retainer’ orthokeratology contact lenses to be worn overnight,” Dr Adams adds. “This possibility will certainly appeal to many people, especially since the changes in the corneal curvature of the treated eye are fully reversible.” ### To read the article, “Refractive Changes from Hyperopic Orthokeratology Monovision in Presbyopes”, please visit http://journals.lww.com/optvissci/Fulltext/2013/04000/Refractive_Changes_From_Hyperopic_Orthokeratology.3.aspx. About Optometry and Vision Science Optometry and Vision Science, official journal of the American Academy of Optometry, is the most authoritative source for current developments in optometry, physiological optics, and vision science. This frequently cited monthly scientific journal has served primary eye care practitioners for more than 75 years, promoting vital interdisciplinary exchange among optometrists and vision scientists worldwide. About the American Academy of Optometry Founded in 1922, the American Academy of Optometry is committed to promoting the art and science of vision care through lifelong learning. All members of the Academy are dedicated to the highest standards of optometric practice through clinical care, education or research. About Lippincott Williams & Wilkins Lippincott Williams & Wilkins (LWW) is a leading international publisher of trusted content delivered in innovative ways to practitioners, professionals and students to learn new skills, stay current on their practice, and make important decisions to improve patient care and clinical outcomes. LWW is part of Wolters Kluwer Health, a leading global provider of information, business intelligence and point-of-care solutions for the healthcare industry. Wolters Kluwer Health is part of Wolters Kluwer, a market-leading global information services company with 2012 annual revenues of ?3.6 billion ($4.6 billion). Contact: Connie Hughes |
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