Biomedical subjects
B Christenson
Publications and source records attributed to B Christenson.
Mass vaccination programme aimed at eradicating measles, mumps and rubella in Sweden: vaccination of schoolchildren.
In 1982-83, a unique, two-dose programme of immunization with a combined vaccine against measles, mumps and rubella was initiated in Sweden. The first dose was administered at 18 months and the second at 12 years of age. A vaccination study was carried out on 247 12 year old schoolchildren from four schools situated in two urban and two rural areas. In urban areas, 30% of children were found to be susceptible to rubella and 18% to mumps, compared with 55% susceptible to rubella and 31% to mumps in rural areas. The reverse was found for measles, to which 20% of children lacked immunity in urban areas but only 6% in rural areas. Seroconversion was seen in 82% against measles, in 80% against mumps and in 100% against rubella. Follow-up studies of the timing and the virus dosage are also to be carried out.
Vaccination against measles, mumps and rubella (MMR): a comparison between the antibody responses at the ages of 18 months and 12 years and between different methods of antibody titration.
In connection with the introduction of the trivalent vaccine against measles, mumps and rubella at 18 months and 12 years of age, an evaluation of the seroconversion and booster effects in the two age-groups was carried out. This also comprised different laboratory-test methods appropriate for follow-up studies after large-scale, vaccination studies. The measles, mumps and rubella antibodies were measured by the haemolysis-in-gel (HIG) method. Measles antibodies were also measured by the haemagglutination-inhibition (HI) test. Borderline values or samples negative to measles or mumps were also tested by the serum-neutralization (SN) test. All but four of 150 18-month-old children lacked antibodies against measles by the HI test and one of these by the HIG method. Against mumps, 99% were seronegative in the HIG test and 97% in the SN test and two against rubella prior to vaccination. Among 247 schoolchildren, 60 (24%) lacked antibodies in the HI test and 28 (11%) of these also in the HIG test. Sixty-six schoolchildren (25%) were negative to mumps and 45% to rubella prior to vaccination. The seroconversion rate for the 18-month-old children was 96% against measles, 93% against mumps and 99% against rubella. The figure for the schoolchildren was 82% against measles, 80% against mumps and 100% against rubella. On comparing the titre levels in seroconverting children, the measles-antibody levels were found to be lower among older children, compared with younger, while the opposite was true for rubella.(ABSTRACT TRUNCATED AT 250 WORDS)
Typhoid fever among Swedish visitors to Kos in 1983.
Seven cases of confirmed typhoid fever were discovered among 26 Swedish visitors to the Greek island of Kos in 1983. They had all stayed at the same hotel during the last week of June and the first week of July. During the same period 32 British visitors and 16 visitors from other Scandinavian countries who stayed at the implicated hotel also developed typhoid fever. By analysing questionnaires and by personally interviewing the Swedish visitors, a close association with the eating of salad at dinner on the 4th of July was found. As soon as the first Swedish case was discovered, a carrier among the hotel staff was suspected because it was known that one Swedish and one Finnish case of typhoid fever had been reported in 1981 and 1982 respectively, both patients having stayed at the implicated hotel.
Acute infections with hepatitis B virus in medical personnel during a 15-year follow-up.
Clinical hepatitis B among hospital staff in Sweden was studied in a 15-year follow-up, divided into three periods. During the first 5-year period, 1969-1973, 756 cases of hepatitis B were reported among hospital staff, for an attack rate of 102.0 per 100,000 person-years. In the second five-year period, 1974-1978, the attack rate was 30.4, and in the last five-year period, 1979-1983, it was 10.4. The decrease in incidence between the first period and the second was significant (p less than 0.001), as was the difference between the second period and the last (p less than 0.01). The difference between the incidence in medical personnel and that in the general population of working age in the first period was significant at p less than 0.001 and during the last period it was significant at p less than 0.01. No statistical significance was found during the second period, due to the decrease in incidence for both groups, which made the values too scattered. Traditionally high-risk units, such as renal dialysis units, had only three cases reported in the last 5-year period. An overrepresentation of males among nurses and nursing assistants with acute hepatitis B was found.
In vitro susceptibility of Neisseria gonorrhoeae to 2-acetylpyridine thiosemicarbazones.
MICs of 20 2-acetylpyridine thiosemicarbazones and penicillin were determined for 25 clinical isolates of beta-lactamase-positive and beta-lactamase-negative Neisseria gonorrhoeae strains. The compounds most active against the beta-lactamase-producing strains were the N4,N4-disubstituted derivatives and the thiosemicarbazone derivatives of the 2-acetylpyridines, followed by the other compounds related to the 2-acetylpyridine thiosemicarbazones.
Epidemiological aspects of acute viral hepatitis A in Swedish travellers to endemic areas.
A decreased incidence of hepatitis A (HA) in Swedish travellers to the northern part of the Mediterranean area was observed after 1972, from 1/3 000 travellers who did not receive gammaglobulin in the period 1970-72 to 1/14 200 travellers between 1979 and 1981 and 1/20 000 travellers in 1982. No such decrease in incidence was observed in travellers going to the southern part of the Mediterranean area. Differences in the incidences of HA in travellers to individual countries in southern Europe were also noticed. The risk of Swedish travellers to remote destinations, such as tropical Africa and Asia, contracting HA is still very high, being 1/150-100 travellers not receiving gammaglobulin. It was observed that years with high incidences of HA in travellers to certain destinations also saw increased incidences of HA in Sweden.
Cryptococcal meningitis.
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An outbreak of tularemia in the northern part of central Sweden.
An extensive epidemic of tularemia with 529 cases, 400 of which were confirmed by laboratory tests, occurred in the northern part of central Sweden during the summer of 1981. The outbreak was of short duration and was restricted to certain communities within a narrow geographical area. It began in the middle of July and progressed during that month and August, with only sporadic cases in September and October. During the 2 years preceding the outbreak only 3 and 7 cases were reported in Sweden. The infection was mainly transmitted by mosquitoes and most cases were ulceroglandular. The later cases in September and October were infected by contact with hares or rodents. All age groups were affected, with a slight predominance of women and the 30-60 yr age groups.
Chlamydial pneumonia: a review.
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[Serologic indicators in infection by hepatitis virus type B].
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Mass vaccination programme aimed at eradicating measles, mumps, and rubella in Sweden: first experience.
General vaccination with a combined measles, mumps, and rubella vaccine was introduced in Sweden in 1982. The immunisation schedule comprises two vaccine injections, given at 18 months and 12 years of age, respectively. A controlled field study was carried out in 150 children aged 18 months using two different batches of the vaccine. Seroconversion was seen in 96% against measles, 93% against mumps, and 99% against rubella--the same rates with both vaccine lots. Nevertheless, a difference was noted between the two batches with respect to postvaccination reactions. Fever and rash were recorded mainly five to 12 days after vaccination. Moderate fever (38.5-39.4 degrees C) was observed in 22 children, high fever (greater than or equal to 39.5 degrees C) in 33, and rash in 35. Preliminary results obtained by follow up of routinely vaccinated schoolchildren aged 12 indicated considerably lower rates of fever and rash during the postvaccination period, occurring in 3-10% of cases only. These findings show that complete eradication of measles, mumps, and rubella in Sweden is entirely practicable by the mass vaccination programme and that side effects of vaccination are likely to be few and mild.
The immunizing effect and reactogenicity of two live attenuated mumps virus vaccines in Swedish schoolchildren.
An evaluation of the seroconversion and booster effects after vaccination with two different mumps vaccines, the Urabe Am 9 strain and the Jeryl Lynn strain, was carried out in schoolchildren. Four hundred and fifty-four schoolchildren aged 11 to 12 years with no previous history of mumps or mumps vaccination were enrolled for the study. The antibody responses were measured by serum neutralization (SN) and haemolysis-in-gel (HIG) tests. Of the 454 subjects, 130 were found to be initially seronegative. Two lots of different strengths of each vaccine were used to evaluate the relationships. The Urabe Am 9 vaccine lots had infectivity titres of 100 000 and 19 000 TCID50 per dose and the Jeryl Lynn vaccine titres of 59 000 and 28 000 TCID50 per dose. Only slight differences in seroconversion rates were seen between the lots. The overall seroconversion rate, measured by SN, was 94% for the Urabe Am 9 vaccine and 91% for the Jeryl Lynn vaccine, whereas the geometric mean titre for virus-neutralizing antibody in seroconverting children was 7.4 with the Urabe Am 9 vaccine and 10.7 with the Jeryl Lynn vaccine. In children who were seropositive prior to vaccination, a marked rise in antibody titre was found 8 weeks after vaccine injection indicating a booster effect. The miscellaneous post-vaccination side-effects were mild and inconsequential.
HSV 2-associated antigens in human cervical tissues before and after grafting in nude mice.
Biopsy material from human invasive cervical carcinoma, carcinoma in situ (CIS) and normal uterine cervix was transplanted into nude mice, some of which were then injected with estrogen or progesterone during a follow-up of 1-4 weeks. The cervical cells were analysed prior to and after passage in nude mice by the anticomplement immunofluorescence (ACIF) assay for the presence of herpes virus associated antigens. Such antigens were found in a few cells in three out of seven transplanted cervical cancers prior to the grafting and in one out of 3 cases with normal tissue. After the grafting period HSV-related antigen was found in 6 out of 7 cases of cervical cancer in grafting material from estrogen-stimulated mice. Without hormonal stimulation, 5 out of 7 showed a positive reaction. Hence the expression of the HSV-related antigen seemed enhanced after grafting in nude mice.
An outbreak of campylobacter enteritis among the staff of a poultry abattoir in Sweden.
In the middle of June 1980 an explosive outbreak of campylobacter enteritis occurred among the staff of a poultry abattoir in southern Sweden. In all 37 cases of acute gastroenteritis originating from the abattoir were reported and Campylobacter jejuni was isolated from the stools in 24 of them. When the outbreak occurred, a large proportion of the ordinary staff had been replaced by inexperienced teenagers working during their holidays. A specially big slaughter had also taken place the same week as these inexperienced workers had started. The holiday workers contracted the disease to a greater extent (71%) than the ordinary staff (29%). An overall screening revealed 5 asymptomatic carriers among the ordinary staff. In 3 cases secondary spread was found.
[Acquired immunodeficiency syndrome].
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