Document text
Evidence to Recommendations and proposed
recommendations for use of virus -like particle
chikungunya vaccine among laboratory workers
Dr J. Erin Staples
Arboviral Diseases Branch
Centers for Disease Control and PreventionNational Center for Emerging and Zoonotic Infectious Diseases
April 16 , 2025
Infections among laboratory workers
•At least 44 chikungunya virus infections identified among laboratory
workers worldwide over ~50 years1–3
-43 cases overt disease, 1 asymptomatic infection, no deaths
•4 disease cases in US laboratorians since chikungunya became notifiable disease in 2015
•Identified cases underestimate all infections as no formal laboratory surveillance system
1. The Subcommittee on Arbovirus Laboratory Safety of the American Committee on Arthropod -Borne Viruses. Am J Trop Med Hyg 1980;
2. Rusnak JM, et al. J Occup Environ Med 2004; 3. US national arboviral disease surveillance system, 2015– 2024
Routes of transmission in the laboratory
•Aerosol
•Percutaneous
-Needlestick while working with and
injecting mice
-Forceps prick while dissecting mosquitoes infected with chikungunya virus
•Mucosal (possible)
•Three main genotypes of chikungunya virus (Asian, West African, and
East/Central/South African [ECSA])
-CHIK -VLP based on West African genotype virus, most genetically distinct
-Chikungunya virus strains generally considered to constitute single serotype
•Non -human primates (NHPs) immunized with virus -like particles were protected
from challenge with ECSA chikungunya virus strain1
-No NHP challenge studies with Asian genotype virus strain
•Sera from vaccinated persons showed neutralization of all genotypes2,3
-Some variability in neutralizing antibody titers between lineages
•CHIK -VLP will likely cross -protect against all virus strains but not provenCross- protection against different chikungunya virus genotypes
by chikungunya virus -like particle vaccine (CHIK -VLP)
1. Akahata W et al, Nat Med 2010. 2. Goo et al, J Infect Dis 2016. 3. Chang LJ et al, Lancet 2014.
Should chikungunya virus -like particle vaccine be recommended for
laboratory staff at risk for chikungunya virus infection?Policy question
Domain: Public Health Problem
Topic Decision Considerations
Public health
problemNo, not of public health importance overall•Only occasional laboratory -acquired
infections reported in United States
•For laboratorians potential exists for acute infection with severe polyarthralgia and possible chronic arthralgia
Domain: Benefits and Harms*
Topic Decision Considerations
Benefits and
HarmsDesirable anticipated effects of vaccination are moderate•Very good short -term seroresponse rates
•Limited long -term seroresponse data;
sustained protection important for staff if work in laboratory for many years
•CHIK -VLP likely protects against all
chikungunya virus genotypes but not proven
Undesirable anticipated effects of vaccination are small•Rates of serious adverse events and all arthralgia/arthritis outcomes not significantly different between vaccinated and placebo groups in clinical trials
*Based on GRADE assessment
Domain: Benefits and Harms*
Topic Decision Considerations
Benefits and
HarmsDesirable effects outweigh the undesirable effects (favors intervention)•Acceptable immunogenicity and safety results from clinical trials
•Prevention of potentially severe illness
Certainty of evidence for
prevention of disease: Low
(short -term efficacy) and very
low (long -term efficacy)
Certainty of evidence for
potential adverse events: Low•Review of clinical trial data in GRADE
assessment
*Based on GRADE assessment
Domain: Values
Topic Decision Considerations
Values Laboratorians likely think
desirable effects large relative to
undesirable effects
No important variability•Scientists understand risks of disease and
risks and benefits of vaccination
Acceptability Yes, acceptable to key stakeholders•Acceptable for occupational health
directors, laboratory managers, and
laboratorians because will improve safety
Domain: Acceptability
Topic Decision Considerations
Values Laboratorians likely think
desirable effects large relative to
undesirable effects
No important variability•Scientists understand risks of disease and
risks and benefits of vaccination
Acceptability Yes, acceptable to key stakeholders•Acceptable for occupational health
directors, laboratory managers, and
laboratorians because will improve safety
Domain: Resource Use
Topic Decision Considerations
Resource use Yes, reasonable and efficient
allocation of resources•Vaccination for limited number of staff undertaking research or specific diagnostic work with chikungunya virus
•Small cost to avoid impact and costs of worker becoming infected
Equity Probably increased •If employer offers vaccination, will improve safety for staff and addresses an
occupational health issue
Feasibility Yes, feasible •Likely incorporated into existing
occupational health program
Domain: Equity
Topic Decision Considerations
Resource use Yes, reasonable and efficient
allocation of resources•Vaccination for limited number of staff undertaking research or specific diagnostic work with chikungunya virus
•Small cost to avoid impact and costs of worker becoming infected
Equity Probably increased •If employer offers vaccination, will improve safety for staff and addresses an
occupational health issue
Feasibility Yes, feasible •Likely incorporated into existing
occupational health program
Domain: Feasibility
Topic Decision Considerations
Resource use Yes, reasonable and efficient
allocation of resources•Vaccination for limited number of staff undertaking research or specific diagnostic work with chikungunya virus
•Small cost to avoid impact and costs of worker becoming infected
Equity Probably increased •If employer offers vaccination, will improve safety for staff and addresses an
occupational health issue
Feasibility Yes, feasible •Likely incorporated into existing
occupational health program
Balance of consequences for CHIK- VLP vaccination of
laboratory workers at risk for chikungunya virus infection
o Undesirable
consequences clearly outweigh desirable consequences in most settingso Undesirable consequences probably outweigh desirable consequences in most settingso The balance between desirable and undesirable consequences is closely balanced or uncertaino Desirable
consequences
probably
outweigh
undesirable
consequences
in most settingso Desirable
consequences clearly outweigh undesirable consequences in most settingso There is insufficient evidence to determine the balance of consequences
ACIP recommends virus- like particle chikungunya vaccine for laboratory
workers with potential for exposure to chikungunya virus.*Draft recommendation for CHIK -VLP vaccination for
laboratory workers
*Consistent with language of recommendation for vaccination of laboratory workers with live attenuated
chikungunya vaccine approved by ACIP in February 2024
•Local biosafety committee should undertake risk assessment of potential
for chikungunya virus exposure considering
-Type of work to be performed
-Biosafety level at which work is being conducted
•Vaccination not necessary for workers handling routine clinical samples Information accompanying recommendations
ACIP recommends virus- like particle chikungunya vaccine for laboratory
workers with potential for exposure to chikungunya virus.Draft recommendation for CHIK -VLP vaccination for
laboratory workers
ACIP Chikungunya Vaccines Work Group
Arboviral Diseases Branch, CDC
•Susan HillsAcknowledgments
For more information, contact CDC
1-800- CDC- INFO (232 -4636)
TTY: 1 -888- 232- 6348 www.cdc.gov
The findings and conclusions in this report are those of the authors and do not necessarily represent the official position of the Centers for Disease Control and Prevention.