Letters to the Editor: Varicella vaccination (original) (raw)
Related papers
The Case against Universal Varicella Vaccination
International Journal of Toxicology, 2006
In 1995, the United States became the first country to implement a Universal Varicella Vaccination Program. Several questions remain: Is the varicella (chickenpox) vaccine needed? Is it cost effective as a routine immunization for all susceptible children? Or is it more beneficial for the disease to remain endemic so that adults may receive periodic exogenous exposures (boosts) that help suppress the reactivation of herpes zoster (shingles). In addition, as vaccination coverage becomes widespread, does loss of immunologic boosting cause a decline in vaccine efficacy and result in a reduced period of immunity? Scientific literature regarding safety of the varicella vaccine and its associated cost-benefit analysis have often reported optimistic evaluations based on ideal assumptions. Deleterious outcomes and their associated costs must be included when making a circumspect assessment of the Universal Varicella Vaccination Program.
Medical Veritas: The Journal of Medical Truth, 2005
Varicella vaccination is generally considered safe but there are usually no prescreening tests to determine whether an adverse reaction is likely to occur. The literature contains a surprising number of adverse reactions following varicella vaccination including vaccine-strain herpes-zoster (HZ) in children and adults. The Advisory Committee on Immunization Practices (ACIP) states, "VAERS data are limited by underreporting and unknown sensitivity of the reporting system, making it difficult to compare adverse event rates following vaccination reported to VAERS with those from complications following natural disease. Nevertheless, the magnitude of these differences makes it likely that serious adverse events following vaccination occur at a substantially lower rate than following natural disease." Since follow-up is not conducted, it may be argued that some reports may not be attributed to or associated with vaccination and therefore the true rate of adverse events is essentially unknown. Nevertheless, adverse reactions reported in VAERS have typically been shown to be only 5% or 10% of the true rates. Cost-benefit analyses of the universal varicella vaccination program appear to be optimistic, especially when adverse vaccine reactions are completely ignored or excluded.
Journal of Preventive Medicine and Hygiene, 2016
Summary Influenza is a serious public health problem, since seasonal epidemics affect approximately 5-10% of the population and thus give rise to a heavy social and healthcare burden. The heavy burden of disease is due to several factors, one of which is the biological features of the pathogen. Indeed influenza viruses display high mutation rates and undergo frequent genetic reassortment. Minor variations cause seasonal epidemics and major variations, which result from the hybridization of viruses typical of different animal species, can lead to pandemics. Vaccination remains the most efficacious means of mitigating the harmful healthcare and social effects of influenza. Influenza vaccines have evolved over time in order to offer broader protection against circulating strains. Trivalent vaccines containing two A viruses and one B virus are currently available. However, given the co-circulation of both B virus lineages (B/Yamagata and B/Victoria), quadrivalent vaccines have recently ...
Continuing Medical Education, 2003
Chicken pox (varicella) is erroneously regarded as a trivial, self-limited infection of children.While the death rate in children is below 2/100 000, it rises more than 15-fold in adults. 1 Prior to the introduction of antiviral medication, the mortality rate in leukaemic children was 7%, 3 500-fold higher than in immunocompetent children. 2 Ninety per cent of cases of chicken pox occur in children younger than 13 years of age. However, 10% of adolescents and adults are still susceptible to varicella. For example, Waner showed that 10% of medical students attending the University of the Witwatersrand were susceptible. 3
Influenza is one of the most common respiratory diseases in the world, annually causing over one million of deaths� It is triggered by one of the influenza viruses (A, B, or C)� In most cases, it occurs in epidemic form, but it can also appear in pandemic form, and very occasionally, it occurs in sporadic form� In the temperate zones, influenza occurs during the winter months of a year� In the tropics, however, it occurs throughout the year, although the highest number of patients is registered during the rainy seasons� In young and otherwise healthy individuals influenza is a mild disease; however, if affecting individuals with a weakened immune system, it can lead to health complications and even to death� The only effective preventive measure to preclude the disease is vaccination� There is still no consensus on whether the vaccination should be compulsory or recommended and which population groups should be vaccinated� In most European countries, the vaccination is recommended for some population groups, while in the United States the vaccination is recommend to all individuals above six months of age�
Vaccination to prevent varicella
Human & Experimental Toxicology, 2013
Background: There is increasing evidence that herpes zoster (HZ) incidence rates among children and adults (aged <60 years) with a history of natural varicella are influenced primarily by the frequency of exogenous exposures, while asymptomatic endogenous reactivations help to cap the rate at approximately 550 cases/ 100,000 person-years when exogenous boosting becomes rare. The Antelope Valley Varicella Active Surveillance Project was funded by the Centers for Disease Control and Prevention in 1995 to monitor the effects of varicella vaccination in one of the three representative regions of the United States. The stability in the data collection and number of reporting sites under varicella surveillance from 1995-2002 and HZ surveillance during 2000-2001 and 2006-2007 contributed to the robustness of the discerned trends. Discussion: Varicella vaccination may be useful for leukemic children; however, the target population in the United States is all children. Since the varicella vaccine inoculates its recipients with live, attenuated varicella-zoster virus (VZV), clinical varicella cases have dramatically declined. Declining exogenous exposures (boosts) from children shedding natural VZV have caused waning cell-mediated immunity. Thus, the protection provided by varicella vaccination is neither lifelong nor complete. Moreover, dramatic increases in the incidence of adult shingles cases have been observed since HZ was added to the surveillance in 2000. In 2013, this topic is still debated and remains controversial in the United States. Summary: When the costs of the booster dose for varicella and the increased shingles recurrences are included, the universal varicella vaccination program is neither effective nor cost-effective.
Vaccine, 2013
In a cooperative agreement starting January 1995, prior to the FDA's licensure of the varicella vaccine on March 17, the Centers for Disease Control and Prevention (CDC) funded the Los Angeles Department of Health Services' Antelope Valley Varicella Active Surveillance Project (AV-VASP). Since only varicella case reports were gathered, baseline incidence data for herpes zoster (HZ) or shingles was lacking. Varicella case reports decreased 72%, from 2834 in 1995 to 836 in 2000 at which time approximately 50% of children under 10 years of age had been vaccinated. Starting in 2000, HZ surveillance was added to the project. By 2002, notable increases in HZ incidence rates were reported among both children and adults with a prior history of natural varicella. However, CDC authorities still claimed that no increase in HZ had occurred in any US surveillance site. The basic assumptions inherent to the varicella cost-benefit analysis ignored the significance of exogenous boosting caused by those shedding wild-type VZV. Also ignored was the morbidity associated with even rare serious events following varicella vaccination as well as the morbidity from increasing cases of HZ among adults. Vaccine efficacy declined below 80% in 2001. By 2006, because 20% of vaccinees were experiencing breakthrough varicella and vaccine-induced protection was waning, the CDC recommended a booster dose for children and, in 2007, a shingles vaccination was approved for adults aged 60 years and older. In the prelicensure era, 95% of adults experienced natural chickenpox (usually as children)-these cases were usually benign and resulted in long-term immunity. Varicella vaccination is less effective than the natural immunity that existed in prevaccine communities. Universal varicella vaccination has not proven to be cost-effective as increased HZ morbidity has disproportionately offset cost savings associated with reductions in varicella disease. Universal varicella vaccination has failed to provide long-term protection from VZV disease.
Impact of Vaccination on the Epidemiology of Varicella
WHAT'S KNOWN ON THIS SUBJECT: Varicella vaccine is effective, but there is concern that widespread use in young children may lead to a shift in the age of infection, with potentially more severe disease later in childhood and adolescence. WHAT THIS STUDY ADDS: This study documents that varicella vaccine resulted in a decline of varicella incidence and hospitalization in all age groups, with no shift to older age groups. abstract BACKGROUND: When varicella vaccine was licensed in the United States in 1995, there were concerns that childhood vaccination might increase the number of adolescents susceptible to varicella and shift disease toward older age groups where it can be more severe.