Drug Safety

, Volume 26, Issue 9, pp 599–604

Mass Psychogenic Illness After Vaccination

Leading Article


When vaccines are administered to groups, the physical reactions of the recipients may be similar, causing a form of mass reaction, the mechanism for which is the same as that for mass reactions from other causes. These phenomena have been categorised as mass psychogenic illness (MPI), and have been defined as the collective occurrence of a constellation of symptoms suggestive of organic illness but without an identified cause in a group of people with shared beliefs about the cause of the symptom(s). A review of the literature shows that such outbreaks have been reported in differing cultural and environmental settings including developing and industrialised countries, in the work place, on public transport, in schools, and the military. The perceived threats have been against agents such as food poisoning, fire and toxic gases. Whatever the place or perceived threat, the response seems to be similar. The symptoms generally included headache, dizziness, weakness, and loss of consciousness.

Once under way, MPIs are not easy to stop. Incidents reported in the literature show that they can quickly gather momentum and can be amplified by the press who disseminate information rapidly, escalating the events. Management of such mass events can be extremely difficult. Should the public health official in charge continue to try and determine the cause, or should this person call off the entire investigation? It is suggested here that once vaccines are identified as a probable cause of the phenomenon, a dismissive approach may actually be harmful. Unless the spokesperson has already earned a high level of trust, the public are not likely to be convinced easily that nothing was wrong with the vaccine until it has been tested.

An increased awareness of MPIs on the part of organisers of future mass vaccination campaigns seems appropriate. Immunisation managers should be aware that mass immunisation campaigns could generate such mass reactions. It is therefore essential that surveillance/reporting systems for reporting adverse events be improved before such campaigns. A mass campaign using a smallpox vaccine should be accompanied by a surveillance system capable of distinguishing between multiple cases of conventionally understood vaccine reactions and outbreaks of mass psychogenic illness.


  1. 1.
    Kharabsheh S, Al Otoum H, Clements CJ, et al. Mass psychogenic illness following Td vaccine in Jordan. Bull WHO 2001; 79(8): 764–70PubMedGoogle Scholar
  2. 2.
    Reported through Reuters via ABC News [online] Available from URL: http://hvlib.integris-health.com/HealthNews/reuters/NewsStory0712200233.htm [Accessed 2003 May 10]
  3. 3.
    Yasmy MT, Bahramnezhad A, Ziaaddini H. Postvaccination mass psychogenic illness in an Iranian rural school. Eas Mediterr Health J 1999; 5: 710–6Google Scholar
  4. 4.
    D’Argenio P, Citarella A, Intorcia M, et al. An outbreak of vaccination panic. Vaccine 1996; 14: 1289–90PubMedCrossRefGoogle Scholar
  5. 5.
    Dreger R. Hysteria and adverse reactions to Td in a junior high school setting. British Columbia Health and Disease Surveillance 1992; 1: 50–4Google Scholar
  6. 6.
    Peiro EF, Yanez JL, Carraminana I, et al. Study of an outbreak of hysteria after hepatitis B vaccination [in Spanish]. Med Clin 1996; 107(1): 1–3Google Scholar
  7. 7.
    Philen RM, Kilbourne EM, McKinley TW, et al. Mass sociogenic illness by proxy: parentally reported epidemic in an elementary school. Lancet 1989 Dec 9; II(8676): 1372–6CrossRefGoogle Scholar
  8. 8.
    Hall EM, Johnson JV. A case study of stress and mass psychogenic illness in industrial workers. J Occup Med 1989; 31(3): 243–50PubMedCrossRefGoogle Scholar
  9. 9.
    Sirois F. Epidemic hysteria. Acta Psychiatr Scand 1974; 254Suppl. 252: 1–46Google Scholar
  10. 10.
    Boss L. Epidemic hysteria: a review of the published literature. Epidemiol Rev 1997; 19: 233–43PubMedCrossRefGoogle Scholar
  11. 11.
    Teoh JI, Soewondo S, Sidharta M. Epidemic hysteria in Malaysian schools: an illustrative episode. Psychiatry 1975; 38: 258–68PubMedGoogle Scholar
  12. 12.
    Ebrahim GJ. Mass hysteria in school children: notes on three outbreaks in East Africa. Clin Pediatr 1968; 7(7): 437–8CrossRefGoogle Scholar
  13. 13.
    Goh KT. Epidemiological enquiry into a school outbreak of an unusual illness. Int J Epidemiol 1987; 16(2): 265–70PubMedCrossRefGoogle Scholar
  14. 14.
    Magnavita N. Industrial mass psychogenic illness: the unfashionable diagnosis. Br J Med Psychol 2000; 73(3): 371–5PubMedCrossRefGoogle Scholar
  15. 15.
    Moffatt MEK. Epidemic hysteria in a Montreal train station. Pediatrics 1982; 70: 308–10PubMedGoogle Scholar
  16. 16.
    Moss PD, McEvedy CP. An epidemic of overbreathing among school girls. BMJ 1966; 2: 1295–300PubMedCrossRefGoogle Scholar
  17. 17.
    Robinson P, Szewczyk M, Haddy L, et al. Outbreak of itching and rash: epidemic hysteria in an elementary school. Arch Intern Med 1984; 144: 1959–62PubMedCrossRefGoogle Scholar
  18. 18.
    Walton EA. Outbreak of unexplained illness in a middle school [letter]. J Emerg Med 1996; 14(4): 528CrossRefGoogle Scholar
  19. 19.
    Levine RJ, Sexton DJ, Romm FJ, et al. Outbreak of psychosomatic illness in a rural elementary school. Lancet 1974; II: 1500–3CrossRefGoogle Scholar
  20. 20.
    Pollock GT, Clayton TM. Epidemic collapse: a mysterious outbreak in three Coventry schools. BMJ 1964; II: 1625–7CrossRefGoogle Scholar
  21. 21.
    McEvedy CP, Griffith A, Hall T. Two school epidemics. BMJ 1966; 2: 1300–2PubMedCrossRefGoogle Scholar
  22. 22.
    Struewing JP, Gray GC. An epidemic of respiratory complaints exacerbated by mass psychogenic illness in a military recruit population. Am J Epidemiol 1990; 132(6): 1120–9PubMedGoogle Scholar
  23. 23.
    Pastel RH. Collective behaviours: mass panic and outbreaks of multiple unexplained symptoms. Mil Med 2001; 166(12 Suppl.): 44–6PubMedGoogle Scholar
  24. 24.
    Bartholomew RE, Wessely S. Protean nature of mass sociogenic illness: from possessed nuns to chemical and biological terrorism fears. Br J Psychiatry 2002; 180: 300–6PubMedCrossRefGoogle Scholar
  25. 25.
    Amin Y, Hamdi E, Eapen V. Mass hysteria in Arab culture. Int J of Soc Psychiar 1997; 43(4): 303–6CrossRefGoogle Scholar
  26. 26.
    Modan B, Swartz TA, Tirosh M, et al. The arjenyattah epidemic: a mass phenomenon: spread and trigger factors. Lancet 1983; II: 1472–4CrossRefGoogle Scholar
  27. 27.
    Hefez A. The role of the press and the medical community in the epidemic of “mysterious gas poisoning” in the Jordan west bank. Am J Psychiatry 1985; 142: 833–7PubMedGoogle Scholar
  28. 28.
    Selden BS. Adolescent epidemic hysteria presenting as a mass casualty, toxic exposure incident. Ann Emerg Med 1989; 18 (8): 892–5CrossRefGoogle Scholar
  29. 29.
    Small G, Borus JF. Outbreak of illness in a school chorus: toxic poisoning or mass hysteria. N Engl J Med 1983; 308(11): 632–5PubMedCrossRefGoogle Scholar
  30. 30.
    Centers for Disease Control and Prevention. Outbreak of unexplained illnesses in a middle school. Morb Mortal Wkly Rep 1996; 45: 6–9Google Scholar
  31. 31.
    Jones TF, Craig AS, Hoy D, et al. Mass psychogenic illness attributed to toxic exposure at a high school. N Engl J Med 2000; 342(2): 96–100PubMedCrossRefGoogle Scholar
  32. 32.
    Aldous JC, Ellam GA, Murray V, et al. An outbreak of illness among school children in London: toxic poisoning not mass hysteria. J Epidemiol Community Health 1994; 48(1): 41–5PubMedCrossRefGoogle Scholar
  33. 33.
    Epidemic hysteria [editorial]. BMJ 1979; 2: 408Google Scholar
  34. 34.
    Krug SE. Mass illness at an intermediate school: toxic fumes or epidemic hysteria? Pediatr Emerg Care 1992; 8(5): 280–2PubMedCrossRefGoogle Scholar
  35. 35.
    Jones TF. Mass psychogenic illness: role of the individual physician. Am Fam Physician 2000; 62(12): 2649–56PubMedGoogle Scholar
  36. 36.
    Wessely S. Responding to mass psychogenic illness. N Engl J Med 2000; 342 (2): 129–30CrossRefGoogle Scholar
  37. 37.
    World Health Organization and United Nations Children’s Fund. Measles mortality reduction and regional elimination strategic plan [online]. Available from URL: http://www.who.int/vaccines-documents/DocsPDF01/www573.pdf [Accessed 2003 May 10]

Copyright information

© Adis Data Information BV 2003

Authors and Affiliations

  1. 1.Department of Vaccines and ImmunizationWorld Health OrganizationGeneva, 27Switzerland

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