Is it safe for a patient with Multiple Sclerosis (MS) to sleep with someone who has received the yellow fever vaccine?

Safety of Intimate Contact with Yellow Fever Vaccine Recipients for MS Patients

It is safe for a patient with Multiple Sclerosis (MS) to sleep with someone who has received the yellow fever vaccine, as there is no evidence of person-to-person transmission of the yellow fever vaccine virus through intimate contact.

Understanding Yellow Fever Vaccine Transmission

Yellow fever vaccine contains a live attenuated virus (17D strain), but unlike some other live vaccines, there is no documented evidence of transmission from vaccinated individuals to their close contacts through casual or intimate contact. The Advisory Committee on Immunization Practices (ACIP) guidelines do not list any precautions regarding intimate contact with yellow fever vaccine recipients 1.

Key points about yellow fever vaccine transmission:

• The yellow fever vaccine virus has not been documented to spread from person to person through casual contact, sexual contact, or sleeping arrangements
• The only documented transmission of yellow fever vaccine virus has been through blood products collected from recently vaccinated persons 1
• Blood donation centers should defer donors who received yellow fever vaccine within the preceding 2 weeks 1

MS-Specific Considerations

While the yellow fever vaccine itself is generally contraindicated in MS patients due to potential risks of exacerbation, there are no precautions needed for MS patients regarding contact with vaccinated individuals:

• An increase in MS relapses was noted in some yellow fever vaccine recipients with pre-existing MS 1
• Yellow fever vaccine is generally not recommended for immunocompromised persons, including some MS patients on immunosuppressive therapies 1
• However, a 2021 study suggested that yellow fever vaccination might not worsen the course of relapsing-remitting MS as previously thought 2

Risk Assessment for MS Patients

The risk to an MS patient sleeping with someone who received the yellow fever vaccine can be categorized as follows:

1. Direct transmission risk: None documented through intimate contact
2. Indirect risk: None documented for household contacts or intimate partners
3. Comparison with other live vaccines: Unlike oral polio vaccine (OPV), which has documented household transmission and risk of vaccine-associated paralytic poliomyelitis in contacts 1, yellow fever vaccine has no documented similar risk

Special Considerations

For MS patients on immunosuppressive therapies:

• The concern is primarily about the MS patient receiving the vaccine themselves, not about contact with vaccinated individuals
• A case report from 2024 described a vaccine-derived yellow fever infection in an immunocompromised MS patient on anti-CD20 antibody therapy who received the vaccine directly 3, but this does not suggest risk from contact with vaccinated individuals

Practical Recommendations

1. No special precautions needed: MS patients do not need to avoid intimate contact with yellow fever vaccine recipients
2. Blood donation awareness: The vaccinated partner should not donate blood for 2 weeks after vaccination 1
3. Monitoring: While unnecessary from a transmission perspective, MS patients should continue routine monitoring of their condition as per their regular care plan

Conclusion

Based on available evidence, there is no documented risk of yellow fever vaccine virus transmission through intimate contact. MS patients can safely sleep with individuals who have received the yellow fever vaccine without special precautions.