Revaccination of adults against diphtheria. I: Responses and reactions to different doses of diphtheria toxoid in 30-70-year-old persons with low serum antitoxin levels

Studies of diphtheria antitoxin levels in serum from adult populations have indicated high frequencies of unprotected subjects. Serum from 351 randomly selected Danes between 30 and 70 years old has been assessed for antitoxin concentration; 123 persons among these, who had low antibody levels, received one vaccination with 2 Lf, 5 Lf or 12 Lf diphtheria toxoid. Side-reactions were recorded, and antibody levels were studied 4 weeks later. Antitoxin concentration following vaccination increased markedly to above protective level in 83% of those vaccinated. Of subjects, who could document a complete primary vaccination series, only one receiving 2 Lf 31 years after primary vaccination did not attain protective antitoxin level. Minor local reactions only were recorded among subjects who did not respond serologically to vaccination. Frequencies of more pronounced reactions experienced by serologically responding subjects depended on dose and were 15%, 14% and 23% respectively. It was concluded that a single vaccination of the present adult Danish population will induce protective antibody levels so frequently that the effect of herd immunity will secure against epidemics if future diphtheria outbreaks are experienced. To secure individual protection, vaccination history and/or serological assessments have to be explored in order to decide whether a single vaccination is sufficient.

Immunity against diphtheria 25-30 years after primary vaccination in childhood

In Denmark primary vaccination against diphtheria is offered in the 5th, 6th, and 15th month of life with doses of 50 Lf. Only those doing military service are routinely revaccinated (with 12 1/2 Lf, given once). 403 persons offered primary vaccination 25-30 years ago were screened for diphtheria antitoxin titres by the use of neutralisation and haemagglutination tests. 19% of these (10% of the males and 26% of the females) were unprotected (less than 0.01 IU/ml). Among those not revaccinated 22% had antitoxin titres below protective level. This accords with the continuing decline of diphtheria antitoxin titre after vaccination. Among those revaccinated against diphtheria in adolescence 5% became unprotected. Thus, persons who were offered primary vaccination against diphtheria 25-30 years ago may be susceptible to diphtheria and its toxic complications. So may those revaccinated more than 10 years ago. Should diphtheria emerge in a community those who received their primary vaccination more than 2 years ago or revaccination more than 10 years ago ought to be revaccinated. Revaccination is also advisable for those travelling to countries with endemic diphtheria. Moreover, since 10% of the present population were unprotected against tetanus it seems advisable to increase the immunity against diphtheria and tetanus by routine revaccination with a combined diphtheria-tetanus vaccine. Only a documented history of vaccinations should be relied on when a decision is being made as to whether to carry out primary vaccination or revaccination.

[Immunity to diphtheria and tetanus in some of the administrative territories of the RSFSR]

The article deals with the state of immunity to diphtheria and tetanus among the adult population in some administrative regions of the RSFSR. Of the children and adults covered by the survey, 91.3-96.7% were found to have protective antibody titers against diphtheria and 98.7-100%, against tetanus. An essential drop in the level of immunity to diphtheria in persons over 18 years of age was revealed: 71.7% of them were nonimmune, which correlated with the high morbidity rate among these persons. At the same time the percentage of adults nonimmune to tetanus was considerably lower than that of adults nonimmune to diphtheria, reaching only 27.1%. The state of immunity to tetanus in adults was found to depend on the seasons.

Diphtheria immunity in Massachusetts--a study of three urban patient populations

To determine the status of diphtheria immunity among our patients, we measured diphtheria antitoxin levels in three separate patient populations. The technique used was toxin neutralization in rabbit skin, which allowed us to evaluate the immune status of individual patients. We studied an emergency room population, a sampling of inpatients from an urban teaching hospital, and a group of older patients from a chronic care hospital. Overall, approximately 80% of patients had adequate diphtheria antitoxin levels in their serum. However, two subgroups emerged with lower levels, with potential nonimmunity. These were certain young patients, either foreign born or with a potentially "immunocompromising disorder," and the elderly chronically ill. We conclude that while overall diphtheria immunity in our patients appears adequate, subgroups with increased risks do exist and immunization for these subgroups should be undertaken.

Population studies of diphtheria immunity using antitoxin radioimmunoassay

A quantitative method for testing serum diphtheria antitoxin levels was set up using a diphtheria antitoxin radioimmunoassay (RIA). The results of this RIA correlated well with the Schick test in 554 subjects and with intradermal neutralization tests in guinea-pigs in a small group of subjects. The RIA was suitable for use on blood collected by fingerprick on to a disc of standard chromatography paper. These discs could be stored at room temperature for at least 1 month. If storage for more than 6 months was required -20 degrees C was found to be better. Experience with this RIA in a total of 2349 subjects indicated that it is more accurate, rapid and less costly than Schick testing. The RIA should prove to be the preferred method for testing diphtheria immunity in population surveys.

Incidence of cutaneous diphtheria in Bangladesh

Corynebacterium diphtheriae (C. diphtheriae) was isolated from 23 (7%) skin ulcers out of 327 cases studied. Eight (33%) of the 23 positive cases belonged to the age group of 6 to 10 years. Of the 19 strains of C. diphtheriae typed, 18 (95%) were gravis and of which 14 (77%) were toxigenic. More than 90% of the C. diphtheriae positive ulcer cases had serum anti-toxin level at or above the protective level as against 49% of control. No diphtheria bacilli were isolated from throat of any of the skin positive cases. All the ulcers from which C. diphtheriae were isolated also harboured other definite wound pathogens. It is believed that the presence of toxigenic C. diphtheriae in skin wound might play an important role in the spread of faucial diphtheriae. It is evident from serum anti-toxin level that infected persons develop natural immunity.

[Diphtheria immunity and its epidemiological significance]

Indirect haemagglutination test for antitoxic diphtheria antibodies was performed on 3503 sera of persons of all age groups. The results demonstrate that a high percentage of juveniles and adults with less than 0.01 IU/ml has either no (48.9% for juveniles, 35.6% for adults) or at 0.01-0.09 IU/ml only insufficient immunological protection (30% and 41%, respectively) against diphtheria and its toxic effects. But even among children up to 14 years of age, 28.5% are completely without and 20.5% without reliably protective antitoxic immunity, despite a high rate of immunization. There is thus a dangerously high epidemic potential of susceptible persons in the population of the Federal Republic of Germany. To erect a barrier of immunity against epidemic spread requires not only immunization of all children, but also re-immunization every five to six years, plus immunization of juveniles and young adults among a selected group with, at present, highest risk of infection. For this purpose there is a diphtheria toxoid of Behringwerke for adults with only 5 IU toxoid/0.5 ml, which, however, after single application produced an antitoxic immunity (greater than or equal to 0.1 IU/ml) in previously sensitized subjects (17 of 49). Of 32 primary seronegative persons 14 reacted to two injections, while a further 18 (36.7%) had no immune response within six weeks even after second injection.

Quantitative assessments of IgG and IgE antibodies to inhalant allergens in patients with atopic dermatitis

Using antigen-binding radioimmunoassays, we have measured class specific antibodies against two major inhalant allergens, antigen P1 from D. pteronyssinus and Rye I from grass pollen, in sera from 69 patients with atopic dermatitis. The results show that many of the patients have IgE ab to these allergens in keeping with their skin tests. In all cases, the IgE ab was paralleled by IgG ab to the same allergen. In many sera, IgE ab to these inhalant allergens made a significant contribution to the total serum IgE. With two other allergens to which these patients had not been exposed, specific IgE ab was detected in only one serum, whereas the 42 sera tested did not contain IgE ab to diphtheria toxin. Eleven of the adult patients with atopic dermatitis had no history of asthma and had strongly positive skin tests. This group of patients had levels of total IgE and specific ab to antigen P1 that were very similar to those found in a comparable group of patients who had both atopic dermatitis and asthma. Our recent finding that allergens applied to the skin can induce delayed eczematous lesions provides a mechanism by which allergens could contribute to skin lesions. Our present results support the view that specific sensitivity to common allergens should be taken into account in considering the causes of these patients' skin lesions.

Status of antitoxic immunity against diphtheria in Japan. A report of the National Epidemiological Surveillance for Important Communicable Diseases

Antitoxic immunity against diphtheria was surveyed during the period from 1962 to 1980. The survey was done by Schick test in the first decade and then by antitoxin titration of sera by the cell culture method in the recent six years. The data show clearly that the successful control of diphtheria has been accomplished in Japan as the result of active immunization. Both single (D) and combined (DP or DPT) vaccines were effective to convert Schick reaction negative. In addition, immunity was greatly improved by the introduction of the combined vaccine and one additional booster injection. However, such subsequent changes in the immunization schedule introduced in 1976 that giving the primary vaccination at older age and the omission of one booster injection at the preschool, has resulted in appearance of a high risk group below three years of age as well as in the lower immunity levels among school children. The data indicate that the continuous surveillance for diphtheria is required in this country.

[Bacterial antibodies and isoagglutinins in intravenous immunoglobulin preparations]

Various lots of intravenous immunoglobulins for passive immunization should contain almost the same, broad, antibody profile and provoke very low frequencies of untoward reactions. From 1976-1982 a study was undertaken to measure the level of antibodies directed against tetanustoxin, diphtheriatoxin, streptolysin O, staphylolysin, and salmonella in up to 82 lots. It is interesting to note that the measured level of antibodies in intravenous immunoglobulins varied only slightly as well qualitatively as quantitatively with one exception: an immunoglobulin of placental origin. The amount of tetanusantitoxin in the majority of lots of that preparation was ten-fold lower than that of the other immunoglobulins. Intravenous immunoglobulins contain generally 3-6 IE/ml antistaphylolysin, 600-1200 IE/ml antistreptolysin O, 10-20 IE/ml tetanusantitoxin, and 1-2 IE/ml diphtheriaantitoxin. Antibodies to salmonella could not be demonstrated. Some of the lots exhibited isoagglutinins up to a dilution of 1 : 4.

Immunisation of adults during an outbreak of diphtheria

In an outbreak of infection due to Corynebacterium diphtheriae in a hospital for mentally subnormal adults sera from 211 members of staff were screened for diphtheria antitoxin titres. Of these, 79 (37%) required immunisation, and a low dose preparation (1 LfU of diphtheria and 10 LfU tetanus toxoids) was offered. Of the 64 subjects who accepted a single immunisation and were subsequently retested, seroconversion to diphtheria toxoid occurred in 45 (70%), the rate being highest in younger adults. Seroconversion to tetanus toxoid occurred in 59% of subjects. Local reactions to the single dose were reported by 29 (43%) subjects, and nine (13%) experienced moderately severe local reactions and systemic symptoms. We conclude that adults should not be vaccinated without previous screening for susceptibility to diphtheria; that neither previous immunisation nor age is reliable in predicting the need for vaccination; and that though a single booster dose of diphtheria toxoid is probably effective in adults under 45, two doses should be given to those in the older age group.

Microlatex test for diphtheria antitoxin

Microlatex test was used to detect quantitatively the diphtheria antitoxin in the serum samples. Microtiter technique using polystyrene latex particles coated with diphtheria toxoid was found to be more convenient and sensitive than flocculation test using sizable amount of reagents.

[Immunity against diphtheria in mothers and their newborns in Hamburg (1980)]

The Diphtheria antitoxin level (indirect haemagglutination) was measured in blood samples respectively cord blood of 185 mothers and their newborns. Protective titers (greater than or equal to 0.1 I.U. Diphtheria antitoxin/ml) were found in 29.2% of the confined women and in 27% of their newborn babies. A review of similar investigations from the literature is given, and diphtheria toxoid boosters are recommended for youngsters and adults to improve the relatively poor immunity status against diphtheria in the population.

[Level of immunity against diphtheria among the personnel of a Hamburg hospital and in the normal population (author's transl)]

Diphtheria antitoxin titres were measured by passive haemagglutination in a total of 4542 blood samples obtained between the end of 1980 and beginning of 1981 from staff at Hamburg hospitals and from randomly selected age-matched persons (1219). Among the hospital personnel 67.5% had no protective diphtheria antitoxin (less than or equal to 0.11 IU/ml), compared with 52% among the control group. Among those aged 15-24 years, 60.2% of staff were unprotected, compared with 46.6% of the control population. The geometric mean value of the diphtheria antitoxins also gave a worse immunity level for hospital personnel (0.08 IU/ml) than the control population (0.14 IU/ml). While geometric mean titre values of hospital staff beyond the age of 45 fell nearly continuously, those in the control population rose with increasing age.

Diphtheria immunity in Mali (mothers and their neonates and children under two years of age

An analysis of diphtheria antibodies (indirect haemagglutination technique) in 85 paired sera of Malian mothers and their newborns (cord blood) showed that all mothers had protective antibody levels (greater than 0.1 I.U./ml). 81 per cent of the neonates demonstrated protective immunity towards diphtheria. Since in Mali respiratory diphtheria is rare, is may be assumed that a silent immunization by skin sores, contaminated with diphtheria germs takes place. This assumption is supported by an analysis of 30 unimmunized 6 to 24 months old babies from whom 10 had protective and 16 low levels of diphtheria antibodies in their sera. By inclusion of 13 further children of the same age group (possibly previously immunized, since they had demonstrable antibodies against tetanus) we found a geometric mean diphtheria antibody titer for all 43 children of 0,08 I.U./ml.

[Diphteric and tetanic antitoxins seric values in the first year of life, before and after immunization an horizontal survey in Mozambic (author's transl)]

Successive evaluations of diphtheritic (AD) and tetanic antitoxin have been made from birth to twelve months in infants receiving at 3, 4 and 5 months an immunization with antidiphtheritic, antitetanic and absorbed antimeasles vaccine. The decrease of AD of maternal origin is not, contrary to common opinion, regularly exponential. Factors influencing the elimination of AD from maternal origin are discussed. An important decrease is often observed after the first immunizing infection. AD level evolution is independent from that to IgG but there is a correspondence at birth in mother and infant between the highest values of AD and the lowest values of total proteides. The commonly observed existence of AD in mother blood indicates the persistence in Maputo of a strong diphteric endemy, and this justifies the association of the antidiphtheritic vaccination to the antitetanic one. After immunization, high levels of antibodies are always reached for tetanic antitoxin and a little less, regularly, for AD. High levels of AD are more frequent in infants having demonstrated no infectious symptoms. Towards the end of the first year, antibodies levels frequently decrease. From these findings possible ways are discussed for immunizing infants in Africa with antitoxins.