Chickenpox vaccine

V. zoster vaccines (chickenpox vaccine) Human diploid cells... 

Chickenpox Chickenpox is a highly contagious viral infection that causes rash-like blisters on the skin surface and mucous membranes. It is generally mild and not normally life-threatening. For adults, the symptoms are more serious and uncomfortable than for children. The disease can also be deadly for some people, such as pregnant women, people with leukemia, or immunosuppressed patients. Varivax (varicella virus vaccine live) from Merck Co. was tested on about 11,000 children and adults and was approved by the FDA in March 1995 as a chickenpox vaccine. 

Varicella virus vaccine. Oka/ Merck strain of live, attenuated varicella virus Varivax Varicella virus vaccine [BIO] Varicella-Zoster virus (VZV) VARIVAX [TR] Varicella virus vaccine live (Oka/Merck) [FDA] Chickenpox vaccine [SY] NDC 0006-4826-00 -4827-00 [NDC]... 

The chickenpox vaccine was especially sensitive to temperature. We couldn t make it consistently with a high enough... 

Gordon Douglas claims he doesn t know how much it cost to finally develop the chickenpox vaccine, or any other vaccine he worked on at Merck, because he never totaled them up by product. You pay for the marketing, research, administrations, and all other costs as the costs are incurred, and therefore they are expensed against current sales, he says. 

The patient s history is also helpful in distinguishing chickenpox from smallpox. Most patients presenting with chickenpox will have no reliable history of having the disease or the chickenpox vaccination, and most patients will recall exposure to a case of chickenpox or Shingles 10-21 days before onset of their symptoms. 

Varicella vaccine. Varicella vaccine is recommended at any visit at or after age 12 months for susceptible children, ie, those who lack a reliable history of chickenpox. Susceptible persons aged >13 years should receive two doses, given at least 4 weeks apart. 

The varicella vaccine is relatively new and has only been recommended for use since 1996, therefore its true impact on chickenpox and herpes zoster is not yet known. Its continued use will undoubtedly change the epidemiology of these diseases. 

Children less than 12 years of age will have a 97% seroconversion rate following a single vaccination. Adolescents and adults more than 13 years old will only have 78% seroconversion after a single inoculation, but will have 99% conversion after the second vaccination administered 4 to 8 weeks after the first. Antibody titers appear to persist for at least 20 years following immunization. Despite excellent seroconversion rates, breakthrough chickenpox is reported at a rate of 1 case per 10,000 doses distributed. Most cases occurred within the first year following vaccination, and were due to wild-type varicella zoster virus. The majority of breakthrough cases were mild and of short duration.12... 

Varicella virus vaccine is recommended for all children 12 to 18 months of age with a second dose prior to entering school between 4 and 6 years of age. It is also recommended for persons above this age if they have not had chickenpox. Persons aged 13 years and older should receive two doses separated by 4 to 8 weeks. 

Currently available live vaccines include measles, mumps, polio, rubella, vaccinia (smallpox), varicella (chickenpox), and yellow fever. All of these are made from viruses. There are two live bacterial vaccines 1) Bacillus of Calmette and Guerin (BCG) vaccine for tuberculosis and 2) oral typhoid. 

Within the first 2 to 3 days of exposure a person will experience symptoms such as malaise, fever, headache, chills, and backache. The fever can last 1 to 5 days. Usually after the fever is gone, a skin eruption or rash appears. It begins as a pimple lesion for 1 to 4 days, becomes blister-like for 1 to 4 days, and then fills with pus for 2 to 6 days. It then forms a crust that falls off 2 to 4 weeks after the first skin lesion appears, leaving pink scars. An important characteristic is that all smallpox lesions in any affected area are generally found in the same state. In contrast, chickenpox lesions are not synchronous they form in crops. Smallpox lesions are also said to be more numerous on the face and extremities rather than the trunk, unlike chickenpox. The case fatality rate in unvaccinated patients is 15 to 40%. In vaccinated people, the fatality rate is <1%. Patients with smallpox are infectious as soon as a rash is evident and remain infectious until their scabs fall off— a duration of about 3 weeks.3... 

Varicella Virus Vaccine (Varivax) [Vaccine] Uses Prevent varicella (chickenpox) Action Active immunization live attenuated virus Dose Adults Feds. 0.5 mL SQ, rqieat 4—8 wk Caution [C, M] Contra Immunocompromised ... 

Three basic approaches are used to control viral diseases vaccination, antiviral chemotherapy, and stimulation of host resistance mechanisms. Vaccination has been used successfully to prevent measles, rubella, mumps, poliomyelitis, yellow fever, smallpox, chickenpox, and hepatitis B. Unfortunately, the usefulness of vaccines appears to be limited when many stereotypes are involved (e.g., rhinoviruses, HIV). Furthermore, vaccines have little or no use once the infection has been established because they cannot prevent the spread of active infections within the host. Passive immunization with human immune globulin, equine antiserum, or antiserum from vaccinated humans can be used to assist the body s own defense mechanisms. Intramuscular preparations of immune globulin may be used to prevent infection following viral exposure and as replacement therapy in individuals with antibody deficiencies. Peak plasma concentrations of intramuscular immune globulins occur in about 2 days. In contrast, intravenously administered immune globulin provides immediate passive immunity. 

Chickenpox or varicella is caused by the varicella zoster virus (VZV). Varicella vaccine is indicated for active immunisation against varicella in healthy subjects and their susceptible healthy close contacts from the age of 12 months onwards. 

Varicella-Zoster Immunization. Immunization against varicella was approved in the United States in 1995 and is administered to children 12 to 18 months of age or older if they have not had chickenpox. It has been shown to be most effective in the year after vaccination however, breakthrough disease was noted but foimd to be mild. Varicella vaccination reduces the number of related deaths, especially in children aged 1 to 4 years,... 

In May 2006 the U.S. Food and Drug Administration approved a live attenuatedVZV vaccine. It is indicated for patients 60 years of age and older who have had a history of chickenpox but not shingles. It has been shown to reduce the incidence of VZV PHN, and the duration and severity of illness. 

A retrospective study in 19 children with renal transplants identified three who developed disseminated varicella, despite a prior history of chickenpox in two and pretransplant varicella vaccination in one (33). The clinical disease was mild and responded promptly to oral aciclovir. Although this was based on very few patients, the incidence of 16% was thought to be unexpectedly higher than that reported in historic controls (0.7-1.9%), and might have resulted from the higher degree of immunosuppression achieved with mycophenolate mofetil. 

A live attenuated Varicella vaccine was developed in 1973 by Takahashi using the Oka strain, which was isolated from a boy with chickenpox and named after the boy. Several producers use this live vaccine strain, for example Biken Institute, Merck, Sharp Dohme, and SmithKline Beecham. Whereas the first Oka strain vaccines needed to be stored at —20°C, subsequent reformulation of the vaccine provided a shelf-life of up to 2 years at -t-2 C, with... 

In an experimental model of multiple sclerosis, repeated high doses of antigen (myelin basic protein) deleted both the clinical and pathological manifestations of the disease. The effects of Varicella vaccine on 50 patients with chronic progressive multiple sclerosis have therefore been studied (3). The patients were immunized with Varicella vaccine and followed for 1 year. All were seropositive for Varicella before immunization and all had rises in Varicella antibodies after being given the vaccine. There was improvement in 14 patients, 4 became worse, and 29 were unchanged. Four patients developed mild chickenpox after immunization. No other untoward adverse effects occurred. 

Oka strain Varicella vaccine (Merck) has been evaluated in immunocompromised children with leukemia in remission (6,7). Most children had chemotherapy stopped 1 week before and 1 week after immunization glucocorticoids were also stopped for 3 weeks (from 1 week before to 2 weeks after immunization). Varicella vaccine was safe, immunogenic, and effective in leukemic children at risk of serious disease or death from chickenpox. The major adverse effect was a mild rash in 50% of the children within 1 month of immunization, about 40% of whom were treated with aciclovir. A mild form of Varicella developed in 14% of immunized children exposed to Varicella (household contacts). The vaccine protected completely against severe Varicella. Leukemic vaccinees were less likely to develop zoster than were comparable children with leukemia who had wild tjrpe Varicella. 

In 1995, live virus Varicella vaccine (Oka strain) was licensed in the USA. Of the 6574 reported adverse events 4% (67.5 per 100 000 doses) after immunization were serious, while the majority were minor reactions, such as rash, redness, or injection site pain (9). About 10% of immunized children developed mild chickenpox. A total 193 vaccinees reported neurological symptoms, including Bell s palsy, convulsions, and demyelinating syndromes febrile seizures accounted for half of the cases of convulsions. There were 14 deaths, but a role for the vaccine was not proven. 

Modified smallpox occurs typically in previously vaccinated people. The prodrome is less severe than in ordinary smallpox and patients are usually afebrile during development of the rash. Skin lesions, generally fewer in number, evolve more quickly, and are more superficial and lack uniformity compared to ordinary smallpox. Modified smallpox is rarely fatal, and is easily confused with chickenpox. 

History No reliable history of chickenpox disease or vaccination 50-80% recall an exposure to chickenpox or shingles 10-21 days before onset No history of recent exposure to chickenpox or Shingles... 

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