The Centers for Disease Control and Prevention (CDC) began recommending a single dose of varicella vaccine in children aged 1 to 13 years old in 1995. Although the incidence of varicella fell by 90 percent after introduction of the vaccine, there was a high rate of breakthrough varicella illness in immunized children and continuing outbreaks of varicella among children despite high rates of vaccination. Studies also showed that the single-dose vaccine's effectiveness was less than 90 percent. Given the evidence, CDC in 2006 began recommending a second dose of the vaccine for children 4 to 6 years old.
Although data suggest that two doses of varicella vaccine are associated with higher levels of antibody than is one dose, this study is the first to assess the clinical effectiveness of two doses of the vaccine in the general population. Eugene D. Shapiro, MD, and colleagues at Yale University and collaborators at Columbia University conducted active surveillance in an area in Connecticut and discovered 71 cases of varicella in children aged 4 or older. None of the children had received two doses of vaccine, 66 (93 percent) had received one dose, and 5 (7 percent) had received no vaccine.
The investigators then compared the effectiveness of two doses of vaccine versus one dose in a case-control study, using 140 matched controls. The effectiveness of one dose in preventing varicella was 86.0 percent, while the effectiveness of two doses was 98.3 percent. According to Dr. Shapiro, "The odds of developing varicella were 95 percent lower in children who had received two doses of the vaccine compared with those who had received only one."
The results of this study suggest that countries immunizing children with only one dose of varicella vaccine should consider changing to a two-dose regimen. But, the authors emphasized, "There should be continued monitoring of the effectiveness of two doses to assure that its high degree of effectiveness is sustained."
In an accompanying editorial, David W. Kimberlin, MD, of the University of Alabama at Birmingham, agreed with the study authors, noting that this study is the first to evaluate the effectiveness of two doses of varicella vaccine in a "real-world" setting. "The high effectiveness of 98.3 percent found in this investigation supports the programmatic change instituted four years ago," Dr. Kimberlin noted.
1) In this study, the odds of developing varicella (chickenpox) were 95 percent lower in children > 4 years of age who had received two doses of the varicella vaccine compared with those who had received only one dose.
2) Of the 71 cases of varicella noted in the study, none of the subjects had received two doses of vaccine.
3) The effectiveness of two doses of vaccine in protecting against varicella in the study population was 98.3 percent.
NOTE: The study and the accompanying editorial are available online. They are embargoed until 12:01 a.m. EST on Wednesday, Jan. 5, 2011:"Effectiveness of 2 Doses of Varicella Vaccine in Children"
John Heys | EurekAlert!
Multi-year study finds 'hotspots' of ammonia over world's major agricultural areas
17.03.2017 | University of Maryland
Diabetes Drug May Improve Bone Fat-induced Defects of Fracture Healing
17.03.2017 | Deutsches Institut für Ernährungsforschung Potsdam-Rehbrücke
The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.
To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
28.03.2017 | Life Sciences
28.03.2017 | Information Technology
28.03.2017 | Physics and Astronomy