Multiple diagnostic techniques identify previously vaccinated individuals with protective immunity against monkeypox.
Approximately 50% of the US population received smallpox vaccinations before routine immunization ceased in 1972 for civilians and in 1990 for military personnel. Several studies have shown long-term immunity after smallpox vaccination, but skepticism remains as to whether this will translate into full protection against the onset of orthopoxvirus-induced disease. The US monkeypox outbreak of 2003 provided the opportunity to examine this issue. Using independent and internally validated diagnostic approaches with >or=95% sensitivity and >or=90% specificity for detecting clinical monkeypox infection, we identified three previously unreported cases of monkeypox in preimmune individuals at 13, 29 and 48 years after smallpox vaccination. These individuals were unaware that they had been infected because they were spared any recognizable disease symptoms. Together, this shows that the US monkeypox outbreak was larger than previously realized and, more importantly, shows that cross-protective antiviral immunity against West African monkeypox can potentially be maintained for decades after smallpox vaccination.
Hammarlund
Erika
E
Vaccine and Gene Therapy Institute, Oregon Health & Science University, 505 NW 185th Avenue, Beaverton, Oregon 97006, USA.
Lewis
Matthew W
MW
Carter
Shirley V
SV
Amanna
Ian
I
Hansen
Scott G
SG
Strelow
Lisa I
LI
Wong
Scott W
SW
Yoshihara
Paul
P
Hanifin
Jon M
JM
Slifka
Mark K
MK
D000818:Animals; D000914:Antibodies, Viral; D003429:Cross Reactions; D004196:Disease Outbreaks; D004197:Disease Reservoirs; D006801:Humans; D045908:Mpox, Monkeypox / Q000276:immunology* / Q000517:prevention & control* / Q000635:transmission; D012589:Sciuridae / Q000821:virology; D012900:Smallpox Vaccine / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology; D013997:Time Factors; D014922:Wisconsin / Q000453:epidemiology; D015047:Zoonoses
D000914:Antibodies, Viral; D012900:Smallpox Vaccine