Letters. Immunisation does not rule out tetanus
BMJ 2000;320:383 ( 5 February )
EDITOR
Shimoni et al illustrate a needed caution to clinicians: do not exclude a diagnosis of tetanus in a patient who has been
fully immunised.1 Their report adds to the list of rare cases of
tetanus that have occurred despite complete immunisation. Although the
authors state that all reported cases of tetanus in the United
States have occurred in people who have not been immunised, this is
not altogether true. A catalogue of the 740 tetanus cases reported by
the Centers for Disease Control since 1982 discloses that of the
minority whose immunisation status was known, 53 cases had completed a
primary series, 22 had received their latest booster between five and
nine years before, and two had received a booster within five years
(table)
> Immunisation status of
patients with tetanus
> in the United States reported by the Centers for Disease Control
_____________________________________________________________________
Immunisation Primary series Latest booster
Years - No of cases - status known - completed - 5-9 years, <5years
_______________________________________________________________________
1995-97 122
56
16
6
2
1989-90 117
57
12
4
0
1987-88 101
46
5
2
0
1985-86 147
NR
9
5
0
1982-84 253
NR
11
5
0
NR = not reported.
_______________________________________________________________________
In light of their patient's adequate immunisation record, Shimoni et
al presume that he should have mounted a protective titre of
neutralising antibody. With this I agree. But against what, in
particular, does this titre confer protectionclinical infection or
fatal infection? The understanding of "protection" was derived from
animal studies that correlated serum concentrations of tetanus
antibody with symptoms of tetanus.2 The threshold of 0.01 IU/ml was
established because guinea pigs with titres above this level were
protected from fatal tetanus, not from clinical tetanus; six of 45
animals with protective levels developed non-fatal tetanus.3
Similarly, in humans, non-fatal tetanus has been described in 10 out
of 64 consecutive patients with antitetanus titres greater than 0.01
IU/ml.4 More recent cases have borne this out.5
A number of rare and exceptional cases of tetanus occur despite
adequate immunisation and protective levels of neutralising
antibodies. Since tetanus is likely to be fatal if not recognised and
treated properly, the caveat from Shimoni et al1 merits repeating:
doctors should entertain the diagnosis of tetanus in the proper
clinical setting, regardless of the patient's immunisation record.
David R Vinson, staff physician.
Department of Emergency Medicine, Kaiser Permanente Medical Center,
Sacramento, CA 95825, USA
drvins@netscape.net
1. Shimoni Z, Dobrousin A, Cohen J, Pitlik S. Tetanus in an immunised
patient. BMJ 1999; 319:1049[Full Text]. (16 October.)
2. McComb JA. The prophylactic dose of homologous tetanus antitoxin.
N Engl J Med 1964;270: 175-178.
3. Sneath PAT, Kerslake EG, Scruby F. Tetanus immunity: the
resistance of guinea pigs to lethal spore doses induced by active and
passive immunization. Am J Hygiene 1937; 25: 464-476.
4. Goulon M, Girard O, Grosbuis S, Desormeau JP, Capponi MF. Les
anticorps antitétaniques: titrage avant séro-anatoxinothérapie chez 64
tétaniques. Nouv Presse Med 1972; 1:3049-3050[Medline].
5. Crone NE, Reder AT. Severe tetanus in immunized patients with
high anti-tetanus titers. Neurology 1992; 42: 761-764[Medline].
© British Medical Journal 2000
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