Oral Polio Vaccine Should Be Avoided
The oral polio vaccine (OPV) must be avoided in this 1-year-old boy because it poses a significant transmission risk to his immunocompromised sister who recently received a renal transplant. 1
Why Oral Polio Vaccine is Contraindicated
Close contacts of immunocompromised patients should not receive live oral polio virus vaccine because they may shed the virus and infect the immunosuppressed individual. 1 This is the only vaccine among the options listed that is explicitly contraindicated for household contacts of immunocompromised persons. 1
Evidence of Transmission Risk
- Vaccine-derived poliovirus can be shed in stool and transmitted to immunocompromised household members, causing severe disease including paralysis. 1
- A documented case involved an Amish infant with SCID who developed vaccine-derived poliovirus infection despite never receiving the vaccine directly—the virus was transmitted from community members who had been vaccinated. 1
- In that outbreak, 35% of the isolated community had serologic or virological evidence of vaccine-derived poliovirus, demonstrating significant transmission potential. 1
Why Other Vaccines Are Safe
Varicella Vaccine (Option A)
- Varicella vaccine can be safely administered to household contacts of immunocompromised patients. 1
- Transmission is rare and limited only to vaccinees who develop skin lesions at the injection site. 1
- If a varicella rash develops after immunization, the risk of transmission is minimal unless blisters develop at the vaccine administration site. 1
- The only precaution needed: if skin lesions develop, avoid close contact with the immunocompromised person until lesions clear. 1
Injectable Influenza Vaccine (Option C)
- Inactivated influenza vaccine (IIV) is strongly recommended for all household contacts of immunocompromised patients. 1
- This is an inactivated vaccine with no transmission risk. 1
- Annual influenza vaccination of household members is critical to provide a "circle of protection" for the immunocompromised sibling. 1
MMR Vaccine (Option D)
- MMR vaccine should be administered to household contacts of immunocompromised patients. 1
- Viral shedding is unlikely and poses little risk of infection to immunocompromised individuals. 1
- The only documented transmission of MMR components involved rubella vaccine virus via breast milk to nursing infants, not through casual household contact. 1, 2
- Measles and mumps vaccine viruses do not transmit from vaccinees. 1
Critical Context for This Case
The 6-year-old sister is particularly vulnerable because:
- She is only 2 months post-renal transplant, placing her in the highest risk period for opportunistic infections. 1
- She is currently on immunosuppressive medications, which severely compromise her ability to fight infections. 1, 3
- Immunosuppressive therapy is the major cause of immunocompromised status in renal allograft recipients. 4
Important Note on Current Practice
In the United States and Canada, only inactivated poliovirus vaccine (IPV) has been available for routine use since 2000. 1 Therefore, in current clinical practice in these countries, this scenario should not occur as OPV is no longer used. However, this question tests the critical principle that OPV is the only standard childhood vaccine that is contraindicated for household contacts of immunocompromised individuals.