Some concern about the use of recombinant vaccinia vaccines in immunosuppressed people has been brought to the fore again following the contamination of a woman from Ohio, United States, with the recombinant vaccinia-rabies glycoprotein virus.
This incident occurred in September 2000 and involved a 28-year-old pregnant woman from Ohio, who was bitten while attempting to remove from her dog's mouth bait containing oral rabies vaccines, meant for racoons. As a result of the bite, the woman sustained mild abrasions on her forearm and a puncture wound that developed into cellulitis of her arm for which she was hospitalized. During her hospitalization, she underwent treatments for necrotic lesions, adenopathy, abscess and a generalized erythroderma with exfoliation. Medical examinations confirmed that the infection was linked to the vaccinia-rabies virus. It took one month of medical treatment before she fully recovered, without any hindrance to her pregnancy. She duly delivered in March 2001.
Another documented incident occurred in May 1984, and involved an asymptomatic HIV-infected United States soldier. Upon enlistment in the military, the patient was administered vaccines which included the following: adenoviruses 4 and 7, measles, bivalent influenza, diphtheria, rubella, trivalent poliomyelitis, tetravalent meningococcus and tetanus. All these vaccines were administered within the first three days of his basic military training, followed by a primary smallpox vaccination at the end of the first week (8 May).
Two and a half weeks after the smallpox vaccination, the patient developed fever, headache, neck stiffness and night sweats. A further one and a half weeks later, after hospitalization for treatment of (cryptococcal) meningitis, the patient was diagnosed to be HIV-positive. While under treatment for meningitis, he developed an ulcer at the (smallpox) vaccination site, with ulcerated lesions nearby. Further complications resulted in pustular lesions on the patient's buttocks and legs, while a skin biopsy revealed acanthosis with degenerative effects of the lower half of the epidermis. Medical examinations showed evidence of vaccinia in the skin lesions. The patient underwent medical treatment for over three months, recovering from some of the infections, such as oral candidiasis and cutaneous anergy. However, the patient eventually, died in December 1985, owing to further complications of his illness caused by T-cell dysfunction.
The two incidents recounted above bring to the fore the potential risk of using recombinant vaccinia vaccines.
In the specific case of the oral rabies vaccines, contained in baits, it is considered that continuous training of personnel in the strategic placement of baits to minimize contact with humans and pets is necessary to avoid complications. Such good sensitization efforts are considered of utmost importance in any successful vaccination programme and should embrace both the public and professionals.
Along this line, what would be the adequate strategy for the use of other recombinant vaccinia vaccines, such as the one developed to control rinderpest in Africa, where many people are known to be immunosuppressed as a result of the HIV epidemic?
Sources:
Infectious Diseases News Brief. 31 August 2001.
Report of the Advisory Committee on Immunization Practices (ACIP). 2001.
The New England Journal of Medicine. 12 March 1987; 23 August 2001.
Archives of Virology. 1989. 107: 225-235.
The Veterinary Record. 13 February 1993.
Revue scientifique et technique. Office international des épizooties. 1994. 13(3).