Smallpox: Residual Antibody after Vaccination

Abstract

In November 2001, United States citizens became acutely aware of the potential for bioterrorism within our borders. With the introduction of anthrax bacilli (Bacillus anthracis) into the U.S. Postal Service system, the threat of other forms of bioterrorism became a reality. Biological terrorism, or bioterrorism, involves the use or the threat of using diseasespreading microorganisms and/or toxins as weapons of mass destruction. The use of B. anthracis as a weapon of terrorism has resulted in a heightened review of other potential bioterrorism agents. Smallpox virus (variola virus) is considered to pose the greatest risk.In 1980 the World Health Organization Smallpox Eradication Program declared that the disease, and the need for a vaccine with possible adverse reactions, had been eliminated (1-3). However, stocks of variola virus were "officially" maintained in the United States and in the Soviet Union for experimental purposes (6). The dissolution of the Soviet Union led to concerns regarding safety control of a number of State properties, including stocks of variola virus. Other unknown illicit smallpox virus sources may exist, and these may serve as a potential for bioterrorism threats.Most adults 35 years old and older were vaccinated for smallpox at least once prior to entering school. An unknown parameter of this smallpox vaccination, however, is the duration of its protection, as determined by the presence of antibody. It is generally accepted that the original vaccination would be protective for about 5 to 10 years, although the World Health Organization Committee on International Quarantine suggested that international travelers be vaccinated within the 3 years prior to travel (5). Multiple vaccinations provide long-term protection (4); however, the duration of antibody from the single original smallpox vaccination has not been recently evaluated. Do adults who received a single vaccination as a child still have any residual antibody? Many individuals are concerned with regard to protection against smallpox infection and specifically with whether they themselves have antibodies. Each serum donor was questioned regarding the number of times he or she was vaccinated.In this study, the presence of humoral antibody in vaccinated and unvaccinated (control) individuals was investigated. Those who had received additional booster vaccinations were noted, and their results were reported separately from those for individuals who had received a single vaccination. As it is not known whether antibody detected by enzyme immunoassay (EIA) is protective, it was of interest to determine if another antibody test would yield similar results. Accordingly, for comparison, 60 of the EIA-tested sera were also examined by serum neutralization (SN). MATERIALS AND METHODSTwo hundred four sera from adults of various ages, but at least 35 years of age, were submitted to the ESOTERIX Infectious Disease Center laboratory by their physicians for the detection of vaccinia virus antibody. All claimed to have been vaccinated as childre...

Monkeypox-Induced Immunity and Failure of Childhood Smallpox Vaccination To Provide Complete Protection

“…For those contacts displaying IgM or T-cell responses, these aspects of immune detection suggest subclinical infection (Table 3). The presence of residual anti-OPX IgG in vaccinated contacts is consistent with other studies that demonstrate longterm persistence of anti-OPX IgG responses after vaccinia (smallpox) vaccination (4,6,8,9,12). However, anti-OPX IgM was observed only in monkeypox cases, with the exception of two vaccinated contacts (Table 3), supporting the use of this assay as a valuable epidemiologic tool for assessing monkeypox disease incidence.…”

An Extremely Diverse CD4 Response to Vaccinia Virus in Humans Is Revealed by Proteome-Wide T-Cell Profiling

“…Antibody responses. While the mechanisms of protection of smallpox by vaccination with vaccinia virus are unclear, antibodies are detected in humans for decades after vaccination (1,15,29,34,37,38,60,75). In macaques, vaccinia virus-induced antibodies are necessary and efficient to protect against monkeypox virus infection (22).…”

Proteome‐wide analysis of the serological response to vaccinia and smallpox

“…Several strains have been fully sequenced although it is unclear what proportion of the proteome is recognized by the immune system or which of these responses are essential for protection against variola. Vaccinia antibodies are detected in humans for many decades after smallpox vaccination [4][5][6]. Moreover, orthopox challenge models in animals indicate that the first line of defense from vaccinia is mediated by antibodies [7][8][9].…”