OBJECTIVES

: Brazil adopted single-dose universal varicella vaccination (UVV) for infants aged 15 months in 2013 (using a combined measles-mumps-rubella-varicella (MMRV) vaccine from GSK), and expanded to a two-dose schedule using monovalent varicella vaccine at age 4 years in 2018. This study estimated the long-term impact and costs associated with different monovalent strategies for the second dose.

METHODS

: A dynamic transmission model was used to assess the impact of UVV from the payer perspective, considering three currently available vaccines: MMRV-GSK/V-MSD, MMRV-GSK/V-GSK and MMRV-GSK/V-Green Cross. These were compared with the single-dose UVV strategy with MMRV-GSK. Coverage was assumed to be 79% for the first dose and 76% for the second dose, based on the current program performance. Costs and outcomes were calculated over a 50-year time horizon with 5% discount rate. Vaccine effectiveness assumptions were tested through sensitivity analyses.

RESULTS

: For the single-dose MMRV-GSK strategy, 83 million varicella cases were projected, with 464,687 hospitalizations and 5,751 deaths. Among three 2 dose strategies, the MMRV-GSK/V-MSD strategy showed the biggest disease reduction: 28.7 million fewer cases, 142,647 fewer hospitalizations and 1,387 fewer deaths. Reductions for MMRV-GSK/V-GSK were 26.8million, 132, 988 and 1,292 and for MMRV-GSK/V-Green Cross were 11.2 million, 52,529 and 592 respectively. Both MMRV-GSK/V-MSD and MMRV-GSK/V-GSK strategies were dominant in cost effectiveness analysis compared to single-dose MMRV-GSK strategy, showing savings in the net direct medical costs of BRL 490 million and 488 million respectively over 50 years. Similar trends in outcomes were observed in sensitivity analyses.

CONCLUSIONS

: Two-dose strategies with MMRV-GSK/V-MSD and MMRV-GSK/V-GSK were both cost saving compared to the one-dose UVV MMRV-GSK strategy in Brazil, however the MMRV-GSK/V-MSD strategy resulted in greater disease reduction and lower net vaccination costs.