***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Background : Two doses of measles – mumps – rubella ( MMR ) vaccine are recommended for elimination of these diseases in countries with universal mass vaccination ; a 2-dose program is also likely to be required for elimination of childhood varicella and has recently been provisionally recommended in the United States . Given the overlap in MMR and varicella vaccination schedules , development of a combined vaccine appears logical and would facilitate the introduction of 2 doses of varicella vaccination in healthy children with no additional injections . Methods : The immunogenicity and safety of a second dose of an experimental MMR – varicella ( MMRV ) vaccine was assessed in an open-label phase III study ( 208136/017 ) in healthy children aged 5 to 6 years who had previously received a first dose of either MMRV ( N = 48 ) or a licensed MMR vaccine ( N = 45 ) in the second year of life . Results : After administration of MMRV at 5 to 6 years of age , all subjects were seropositive for measles , rubella and varicella antibodies and only one subject in the MMRV group remained seronegative for mumps antibodies . Ratios of postover prevaccination geometric mean titers for antibodies against measles , mumps and rubella did not differ between the 2 study groups . A 5.2-fold increase ( 95 % confidence interval : 3.5–7.8 ) in antivaricella antibody geometric mean titers was seen in initially seropositive subjects in the MMRV group after administration of the second vaccine dose . Local symptoms after the second dose of MMRV were more common in the MMRV group than in the MMR group . The incidence of fever was low in both groups compared with that usually seen after a first dose of MMR or MMRV vaccine . Conclusion : This experimental tetravalent MMRV vaccine appears well suited for use in national immunization programs in place of a second dose of MMR or MMR plus varicella in children who have already received a first dose of MMR The purpose of the cost-benefit analysis described in this article is to determine the economic value of  vaccination of healthy children against varicella in France . It is based on the results of two specific investigations -- an epidemiological model and a prospect i ve observational study ( 1832 cases studied ) of the socio-economic consequences of varicella . This cost-benefit analysis was conducted from the viewpoint of the society and that of the patient , for vaccination coverage rates ranging from 10 to 90 % . This analysis demonstrates the value of varicella vaccination when associated with measles-mumps-rubella ( MMR ) vaccination : if varicella and MMR vaccines are co-administered , the vaccination of 80 % of the children against varicella leads to a reduction in medical costs associated with varicella including that of vaccination , ranging from 10 to 77 % according to the values adopted for vaccination costs , varicella treatment costs , discount rate and vaccine efficacy . The results of this study also underline the benefits of a vaccination policy that aims to achieve a high rate of coverage , thereby reaping the highest benefit from vaccination , and also avoiding potential negative consequences 
    Output:
    
DISCUSSION The studies are favorable to the introduction of universal varicella vaccination in Italy , being cost saving and having a positive impact on morbidity .
The quality score of the studies varied greatly : recent analyses were of comparable quality to older studies