Along with its needed effects, this vaccine may cause some unwanted or undesirable effects. Generally, it is well tolerated and most people experience only minor unwanted effects.  Possible side effects include:

• injection site reactions (e.g. redness, mild pain)
• fever
• headache
• drowsiness
• irritability
• joint/muscle pain 

Uncommon:

• allergic reaction (e.g. rash, wheezing, difficulty breathing)

Pneumococcal conjugate vaccine (Pneu-C-20) is made up of 20 strains of pneumococcal (pneumonia) bacteria combined with a carrier protein. When injected, the vaccine in the body familiarizes the immune system to the pneumococcal bacteria. If the person is exposed to the bacteria again, the immune system can mount a quick, specific attack against the bacteria and ultimately resist infection. Protection offered by this vaccine is only against those strains of bacteria from which the vaccine is prepared.

People with impaired immune responsiveness, whether due to the use of immunosuppressive therapy (e.g. corticosteroids), a genetic defect, HIV infection, or other causes, may have a reduced response to this vaccine. This vaccine may not protect 100% of individuals receiving the vaccine.

 Use is not recommended in the following situations:

• prior severe allergic reaction to pneumococcal vaccine
• allergy to any component of the vaccine

As with other vaccines administered intramuscularly, pneumococcal conjugate vaccine should be given with caution to individuals with thrombocytopenia or any coagulation disorder since bleeding may occur following an IM injection in these subjects.

Administration of pneumococcal vaccine should be postponed if suffering from severe acute illness. Immunization should not be delayed because of minor acute illness, with or without fever.

Use in pregnancy: there is no evidence to suggest that the pneumococcal conjugate vaccine poses a risk to the fetus or to the pregnancy.

Use in breastfeeding: Breastfeeding women can be vaccinated with the pneumococcal vaccine.