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Side Effects


JE vaccine is associated with a moderate frequency of local and mild systemic adverse effects.3,4,5,9,10,11,12 Tenderness, redness, swelling and other local effects have been reported in about 20% of vaccinees ( < 1% to 31%). Systemic side effects, principally fever, headache, malaise, rash, and other reactions, such as chills, dizziness, myalgia, nausea, vomiting and abdominal pain have been reported in approximately 10% of vaccinees.

In a study conducted by the CDC less than 5% of the 1,756 US travelers immunized with a three-dose regimen of the vaccine reported headache, flu-like symptoms, fever, and other systemic complaints. Hives and facial swelling were reported in 0.2% and 0.1% of vaccinees, respectively. Local soreness occurred in 5.9% and local redness in 2.9%. There was no increase in the number or severity of reactions with increasing numbers of doses.8

The US Army studied 4,034 personnel from 1987 to 1989.11 Using a two- or three-dose regimen of JE vaccine, arm soreness was described in 22.7%, local redness in 4.8%, headache in 15.2%, and a febrile episode in 5.5%. In another trial evaluating the safety and immunogenicity of a three-dose immunizing series (Day 0, 7, and 30 or Day 0, 7, and 14), performed in 538 adult volunteers in 1990, the Army determined that local soreness and redness occurred in 21% of vaccinees after the first dose, then decreased with subsequent injections (p < 0.0001, Chi-square for downward trend). Systemic symptoms including feverishness, headache and rash occurred in 5% of vaccinees after the first dose, then decreased with subsequent injections (p < 0.001, Chi-square for downward trend).5 Participants who received the third dose on Day 14 reported more side effects than those who received the injection on Day 30. Among these volunteers, 252 received a booster injection of vaccine one year after receiving the first dose of the primary series. Side effects reported after the booster injection included local symptoms of soreness (24.5%) and redness (6.1%) at the injection site and systemic complaints of headache (4.9%), fever (1.6%), and rash (0.8%). Less than 1% of all reported symptoms was graded as severe. No generalized urticaria or anaphylaxis was reported.

Since 1989, an apparently new pattern of adverse reactions has been reported among vaccinees in Europe, North America, and Australia.12,13,14 The reactions have been characterized by urticaria, often in a generalized distribution, or angioedema of the extremities, face, especially of the lips and oropharynx. Three vaccine recipients developed respiratory distress. Distress or collapse due to hypotension or other causes led to hospitalization in several cases. Most reactions were treated successfully with antihistamines or oral steroids; however some patients were hospitalized for parenteral steroid therapy. Three patients developed an erythema multiforme or erythema nodosum and some patients have had joint swelling. Some vaccinees complained of generalized itching without objective evidence of a rash.

An important feature of the reactions has been the interval between vaccination and onset of symptoms. Reactions after a first vaccine dose occurred after a median of 12 hours after immunization (88% of reactions occurred within 3 days). The interval between administration of a second dose and onset of symptoms generally was longer, (median 3 days and possibly as long as 2 weeks). Reactions have occurred after a second or third dose, when preceding doses were received uneventfully.

Between November 1991 and May 1992, the US Navy immunized 35,253 US personnel (marines, other military and dependents) with JE-VAX (japanese encephalitis virus vaccine inactivated) on Okinawa. The overall reaction rate, 62.4 per 10,000 vaccinees (95% confidence interval 54.2 to 70.6) includes persons reporting urticaria, angioedema, generalized itching and wheezing. The reaction rate per 10,000 vaccinees was 26.7 (95% confidence interval 21.3 to 32.1), 30.8 (95% confidence interval 24.6 to 37.0) or 12.2 (95% confidence interval 7.9 to 16.5) after the first, second or third dose, respectively.6 These reactions were generally mild to moderate in severity. Nine out of 35,253 persons immunized were hospitalized (2.6 per 10,000 vaccinees) primarily to allow administration of intravenous steroids for refractory urticaria. None of these reactions were considered life-threatening.

A case-control study conducted as part of the JE immunization campaign in Okinawa found that persons developing these reactions after JE vaccination were more likely to have had a past history of urticaria after hymenoptera envenomation, drugs, physical or other provocations or of idiopathic origins (relative risk 9.1, 95% confidence interval 1.8 to 50.9).6 The vaccine constituents responsible for these adverse reactions have not been identified.

Other serious adverse events reported following vaccination include (1) one case of Guillain-Barré syndrome after JE vaccination has been reported in the United States since 1984 (this patient was diagnosed as having mononucleosis three weeks before the onset of weakness); (2) one case of urticaria, hepatitis and respiratory failure one week after dose 2 (this person showed effusion and infiltrate on chest x-ray and eosinophilia); (3) one case of respiratory and renal failure one week after a dose (this 26-month-old male had infiltrate on chest x-ray and acid fast bacilli in sputum); and (4) one case of newly diagnosed hypertension in a young adult male presenting with a headache several hours after receiving dose one. The relationship of JE-VAX (japanese encephalitis virus vaccine inactivated) to the etiology of these adverse events is unknown.

Optic neuritis has been reported for one patient. In addition to JE-VAX (japanese encephalitis virus vaccine inactivated) , this patient concurrently received a number of other vaccines.15

Fatal myocarditis has been reported in a patient who had recently been given meningococcal vaccine and at least one dose of JE vaccine. Any causal role for the vaccines is unclear.15

Sudden death occurred approximately 60 hours after receiving the first dose of JE vaccine in a 21-year-old US military person with a history of recurrent hypersensitivity and an episode of possible anaphylaxis. This person also received the third dose of plague vaccine approximately 12 to 15 hours prior to the death. There was no evidence of urticaria or angioedema. Cause of death was not established at autopsy.

Surveillance of JE vaccine related complications in Japan from 1965 to 1973 disclosed neurologic events (primarily encephalitis, encephalopathy, seizures, and peripheral neuropathy) in 1 to 2.3 per million vaccinees.16,17 Very rarely, deaths occurred with vaccine-associated encephalitis. Between 1987 and 1989, two cases of neurologic dysfunction were reported from Japan; one of these was a transverse myelitis, while the second included seizures, cranial nerve paresis, cerebellar ataxia, and behavior disorder.17 In 1992, two cases of acute disseminated encephalomyelitis were reported from Japan; one occurred 14 days after the second dose and the second occurred 17 days after a booster dose of JE vaccine. Both cases recovered.18 One case of Bell's Palsy was reported from Thailand.

Reporting of Adverse Events

The National Vaccine Injury Compensation Program, established by the National Childhood Vaccine Injury Act of 1986, requires physicians and other health-care providers who administer vaccines to maintain permanent vaccination records and to report occurrences of certain adverse events to the US Department of Health and Human Services. Reportable events include those listed in the Act for each vaccine and events specified in the package insert as contraindications to further doses of that vaccine.19,20,21

Reporting by parents and patients of all adverse events occurring after antigen administration should be encouraged. Adverse events following immunization with vaccine should be reported by the health-care provider to the US Department of Health and Human Services (DHHS) Vaccine Adverse Event Reporting System (VAERS). Reporting forms and information about reporting requirements or completion of the form can be obtained from VAERS through a toll-free number 1-800-822-7967.19,20,21

Health-care providers also should report these events to the Pharmacovigilance Department, Sanofi Pasteur Inc., Discovery Drive, Swiftwater, PA 18370 or call 1-800-822-2463.

Read the Je-Vax (japanese encephalitis virus vaccine inactivated) Side Effects Center for a complete guide to possible side effects


There are no data on the effect of concurrent administration of other vaccines, drugs (eg, chloroquine, meflaquine) or biologicals on the safety and immunogenicity of JE vaccine.


3. Hoke CH, et al. Protection Against Japanese Encephalitis by Inactivated Vaccines. N Eng J Med 319: 608-614,1988

4.Poland JD, et al. Evaluation of the Potency and Safety of Inactivated Japanese Encephalitis Vaccine in US Inhabitants. J Infect Dis 161: 878-882, 1990

5. DeFraites RF. Immunogenicity and Safety of Japanese Encephalitis Vaccine (Inactivated: Nakayama/BIKEN) in U.S. Army Soldiers: Evaluation of Three Consecutively Manufactured Lots of Vaccine Administered in Two Dosing Regimens. April 30, 1991, and November 12, 1992. Unpublished Data, on file with BIKEN and with Walter Reed Army Institute of Research, Washington, DC

6. Berg WS. Systemic Reactions in U.S. Marine Corps Personnel Who Received Japanese Encephalitis Vaccine. Clin Infect Dis 24:265-266, 1997

8. Unpublished data on file with "BIKEN" and CDC

9. Rojanasuphot S. et al. A field trial of Japanese encephalitis vaccine produced in Thailand. Southeast Asian J Trop Med Publ Health 20: 653-654, 1989

10. Rao Bhau LN, et al. Safety and efficacy of Japanese encephalitis vaccine produced in India. Indian J Med Res 88: 301-307, 1988

11. Sanchez JL, et al. Further Experience with Japanese Encephalitis Vaccine. Lancet 335: 972-973, 1990

12. Japanese Encephalitis Vaccine and Adverse Effects among Travelers. Canada Diseases Weekly Report. Vol. 17-32: 173-177, 1991

13. Andersen MM, et al. Side-Effects with Japanese Encephalitis Vaccine. Lancet 337: 1044, 1991

14. Ruff TA, et al. Adverse Reactions to Japanese Encephalitis Vaccine. Lancet 338: 881-882, 1991

15. Unpublished data on file with Sanofi Pasteur Inc.

16. Kitaoka M. Follow-up on use of vaccine in children in Japan, in McD Hammon W, Kitaoka M, Downs WG eds. Immunization for Japanese encephalitis. Excerpta Medica, Amsterdam 275-277, 1972

17. Unpublished data on file with "BIKEN"

18. Ohtaki E, et al. Acute disseminated encephalomyelitis after Japanese B Encephalitis Vaccination. Pediatric Neurology Vol. 8 No. 2: 137-139, 1992

19. CDC. Vaccine Adverse Event Reporting System - United States. MMWR 39: 730-733, 1990

20. CDC. National Childhood Vaccine Injury Act. Requirements for permanent vaccination records and for reporting of selected events after vaccination. MMWR 37: 197-200, 1988

21. Food and Drug Administration. New Reporting Requirements for Vaccine Adverse Events. FDA Drug Bull 18(2), 16-18, 1988

Read the Je-Vax Drug Interactions Center for a complete guide to possible interactions

Last reviewed on RxList: 11/4/2008
This monograph has been modified to include the generic and brand name in many instances.

Side Effects

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