April 27, 2017
Recommended Topic Related To:


"Patients with a past or current hepatitis B virus (HBV) infection can experience sometimes fatal HBV reactivation if they take any of nine direct-acting antivirals for hepatitis virus C (HCV) infection, the US Food and Drug Administration (FDA) a"...



Side Effects


In clinical trials involving the administration of 7918 doses of COMVAX to 3561 healthy infants 6 weeks to 15 months of age, COMVAX was generally well tolerated. In these studies, infants received COMVAX with licensed pediatric vaccines (n=1745) or investigational vaccines (n=1816). Serious adverse experience data were available for all 3561 infants and non-serious adverse experience data were available for a subset of 1678 infants.

Pivotal Immunogenicity And Safety Study

In the pivotal, randomized, multicenter study, 882 infants were assigned in a 3:1 ratio to receive either COMVAX or PedvaxHIB plus RECOMBIVAX HB at separate injection sites at 2, 4, and 12-15 months of age. Children may have also received routine pediatric immunizations. The children were monitored daily for five days after each injection for injection-site and systemic adverse experiences. During this time, adverse experiences in infants who received COMVAX were generally similar in type and frequency to those observed in infants who received PedvaxHIB plus RECOMBIVAX HB.

The most frequently cited events were mild, transient signs and symptoms of inflammation at the injection site (i.e., pain/soreness, erythema, and swelling/induration), somnolence, and irritability, all of which were prompted for on report cards filled out by parents of vaccinated children. Table 3 summarizes the frequencies of injection-site and systemic adverse experiences within five days of vaccination that were reported among ≥ 1.0% of children in this pivotal trial.

Table 3: Local Reactions and Systemic Complaints Within 5 Days After Injection Reported to Occur in ≥ 1.0%† of Children Given a 3-Dose Course of COMVAX Compared to These Events in Children Given Concomitant Injections of PedvaxHIB and RECOMBIVAX HB

Event Injection 1‡ Injection 2‡ Injection 3
(N=660) %
(N=221) %
Injection Site Reactions
  Pain/Soreness* 34.5 37.6 24.3 25.8 23.9 21.2
  Erythema ( > 1 in.)* 22.4 (2.7) 25.8 (2.7) 25.7 (1.4) 23.5 (3.3) 27.2 (3.0) 24.4 (1.6)
  Swelling/Induration ( > 1 in.)* 27.6 (3.0) 33.5 (4.1) 30.4 (2.9) 31.0 (3.8) 27.2 (3.2) 29.5 (4.1)
Systemic Complaints
  Irritability* 57 46.6 50.7 44.1 32.2 29
  Somnolence* 49.5 47.1 37.4 31.9 21.1 22.3
      unusual, high pitched* 10.6 8.6 6.7 2.3 2.9 3.6
      not otherwise specified 2.3 2.3 1.4 2.3 0.7 1.6
      prolonged ( > 4 hrs.)* 2.4 2.3 0.8 1.4 0.2 0
  Anorexia 3.9 2.3 2 0.9 0.8 0.5
  Vomiting 2.1 1.8 2.5 0.9 1 1.6
  Otitis media 0.5 0 2 1.4 2.7 1.6
  Fever (“F, rectal equiv.)”
    101.0-102.9 14.2 11.9 13.8 12.2 10.5 6.4
     > 103.0 0.8 0 1.6 1.4 2.7 4.3
  Diarrhea 1.7 1.8 0.8 0.9 2.2 0.5
  Upper respiratory infection 0.5 0.5 1.1 0.9 1.3 0.5
  Rash 0.8 0 0.9 0 0.8 0.5
  Rhinorrhea 0.2 0 1.1 0.9 1.3 2.1
  Respiratory congestion 0.6 0.5 1.2 0.9 0.3 0.5
  Cough 0.2 0 0.9 0.5 0.2 1
  Candidiasis, oral 0.3 0.5 0.8 0 0.2 0
  Rash, diaper 0.5 0.5 0.5 0.9 0.2 0
Overall frequency of each event listed above is > 1% even though the frequency after a given dose may be < 1%.
‡Most children received DTP and OPV concomitantly with the first two doses of COMVAX or PedvaxHIB and RECOMBIVAX HB.
*Events prompted for on Vaccination Report Card given to parents/guardians of vaccinees.
** N for injections 1, 2, and 3 equals 655, 639, and 588, respectively, for COMVAX; N for injections 1, 2, and 3 equals 218, 213, and 187, respectively, for PedvaxHIB and RECOMBIVAX HB.
*** Injection site reactions for PedvaxHIB and RECOMBIVAX HB based on occurrence with either of the monovalent components.

Infants Previously Vaccinated with Hepatitis B Vaccine

In a group of infants (N=126) given a three-dose course of COMVAX after previously receiving a dose of Hepatitis B Vaccine (Recombinant) at or shortly after birth, the type, frequency, and severity of adverse experiences did not appear to be greater than those observed in infants in the pivotal study who did not receive hepatitis B vaccine at birth.

Infants 6 Weeks to 15 Months of Age

In clinical trials, 3285 doses of COMVAX were administered to 1678 infants who were monitored for injection-site and systemic adverse experiences from Days 0 to 5 after each injection of vaccine. Of these, 855 infants had safety data following vaccination at approximately 2 months of age, 836 infants at approximately 4 months of age and 1573 infants at 12 to 15 months of age. The most frequently reported adverse experiences ( ≥ 1% of subjects for at least one injection), without regard to causality are listed in decreasing order of frequency within each body system:

Injection Site Reactions: Pain/tenderness/soreness, swelling/induration, erythema; Body as a Whole: Fever; Digestive System: Anorexia, diarrhea, vomiting; Nervous System/Psychiatric: Irritability, somnolence, crying; Respiratory System: Upper respiratory infection, rhinorrhea, cough, rhinitis; Skin: Rash; Special Senses: Otitis media.

Post-Marketing Experience

As with any vaccine, there is the possibility that broad use of COMVAX could reveal adverse experiences not observed in clinical trials. The following additional adverse reactions have been reported with the use of the marketed vaccine.


Anaphylaxis, angioedema, urticaria, erythema multiforme



Nervous System

Seizure, febrile seizures

Potential Adverse Effects

In addition, a variety of adverse effects have been reported with marketed use of either PedvaxHIB or RECOMBIVAX HB in infants and children through 71 months of age. These adverse effects are listed below.




Sterile injection-site abscess; pain at the injection site



Symptoms of hypersensitivity including reports of rash, pruritus, edema, arthralgia, dyspnea, hypotension, and ecchymoses

Cardiovascular System

Tachycardia; syncope

Digestive System

Elevation of liver enzymes


Increased erythrocyte sedimentation rate

Musculoskeletal System


Nervous System

Bell's Palsy; Guillain-Barre Syndrome


Agitation; somnolence; irritability


Stevens-Johnson Syndrome; alopecia

Special Senses

Conjunctivitis; visual disturbances

Adverse Event Reporting

Patients, parents and guardians should be instructed to report any serious adverse reactions to their health-care provider who in turn should report such events to the U.S. Department of Health and Human Services through the Vaccine Adverse Event Reporting System (VAERS), 1-800-822-7967. The health­care provider should inform the parent or guardian of the National Vaccine Injury Compensation Program (NVICP), 1-800-338-2382.

Read the Comvax (haemophilus b conjugate and hepatitis b vaccine) Side Effects Center for a complete guide to possible side effects


Deferral of immunization may be considered in individuals receiving immunosuppressive therapy.

Read the Comvax Drug Interactions Center for a complete guide to possible interactions

This monograph has been modified to include the generic and brand name in many instances.

Last reviewed on RxList: 11/13/2015

Side Effects

Comvax - User Reviews

Comvax User Reviews

Now you can gain knowledge and insight about a drug treatment with Patient Discussions.

Here is a collection of user reviews for the medication Comvax sorted by most helpful. Patient Discussions FAQs

Report Problems to the Food and Drug Administration


You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.

Living Better

Find the secrets to longer life.