How Do Inactivated Bacterial Vaccines Work?

Reviewed on 12/6/2021

How do inactivated bacterial vaccines work?

Inactivated bacterial vaccines are sterile biologic products that provide acquired immunity against certain bacterial infections. Inactivated bacterial vaccines work by stimulating the body’s immune system to produce antibodies against specific types of bacteria, and protect a person from becoming infected when exposed to these bacteria.

Inactivated bacterial vaccines are made from proteins or fragments of disease-causing bacteria grown in culture and then killed (inactivated) to prevent them from causing disease. Inactivated bacterial vaccines also contain substances that preserve and stabilize the vaccine, and boost immune response.

The main component of inactivated bacterial vaccines is the bacterial antigen against which the immune system produces antibodies. If exposed to the particular bacterial infection later in life, the immune system of the vaccinated person identifies the bacteria by the antigen, attacks and kills the bacteria, preventing illness.

Some inactivated bacterial vaccines are conjugated with tetanus or diphtheria bacterial toxoids to improve the immune response. Toxoids are toxins that are chemically altered to eliminate toxicity, but can be recognized as bacterial antigens by the immune system.

Inactivated bacterial vaccines do not provide as strong or long-lasting immunity as weakened live vaccines do, but are effective for people with compromised immunity. Inactivated bacterial vaccines provide immunity against the following bacterial infectious diseases:

  • Anthrax, caused by Bacillus anthracis bacteria
  • Haemophilus influenzae type B (Hib) bacterial infection
  • Meningococcal disease, caused by Neisseria meningitidis bacteria serogroups A, C, Y and W-135
  • Meningococcal disease, caused by Neisseria meningitidis bacteria serogroup B
  • Pneumonia, caused by multiple strains of Streptococcus pneumoniae bacteria
  • Tetanus, caused by Clostridium tetani bacteria

How are inactivated bacterial vaccines used?

Inactivated bacterial vaccines may be administered in a series of doses on a prescribed schedule as intramuscular (IM) injections into the muscle or subcutaneous (SC) injections into the tissue under the skin.

Inactivated bacterial vaccines are approved by the FDA for use in:

Children and adolescents

  • Primary and booster immunization against Haemophilus influenzae type B (Hib) for healthy individuals
  • Hib immunization for children who are immunosuppressed due to:
    • Sickle cell disease
    • Leukemia
    • Human immunodeficiency virus (HIV)
    • Asplenia (absence of normal spleen function)
  • Meningococcal primary and booster immunization for healthy individuals
  • Meningococcal immunization for individuals at high-risk conditions includes:
    • Asplenia
    • Complement deficiency (deficiency in the innate immune surveillance system)
    • Use of complement inhibiting medications
    • HIV infection
    • Community outbreak
    • Travel to endemic/epidemic areas
  • Routine pneumococcal vaccination for healthy individuals
  • Pneumococcal vaccination for individuals at high risk with:
  • Primary and booster tetanus vaccination


  • Pre-exposure prophylaxis for anthrax in people at high risk
  • Post-exposure prophylaxis for anthrax
  • Haemophilus influenzae type B immunization in individuals who have:
    • Asplenia
    • Complement deficiency
    • Undergone hematopoietic (blood cell forming) stem cell transplant
  • Primary and booster meningococcal immunization 
  • Meningococcal immunization for individuals at high-risk conditions that include:
    • Asplenia
    • Complement deficiency
    • Use of complement inhibiting medications
    • HIV infection
    • Microbiologists who are routinely exposed to Neisseria meningitidis
    • Community outbreak
    • Travel to endemic/epidemic areas
  • Pneumococcal vaccination for individuals with:
    • Compromised/suppressed immunity
    • Cerebrospinal fluid leak
    • Cochlear implant
  • Primary and booster tetanus vaccination

What are side effects of inactivated bacterial vaccines?

Side effects of inactivated bacterial vaccines may include the following:

Information contained herein is not intended to cover all possible side effects, precautions, warnings, drug interactions, allergic reactions, or adverse effects. Check with your doctor or pharmacist to make sure these drugs do not cause any harm when you take them along with other medicines. Never stop taking your medication and never change your dose or frequency without consulting your doctor.

What are names of inactivated bacterial vaccines?

Generic and brand names of inactivated bacterial vaccines include:


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