Adverse reactions and antibody responses to acellular pertussis vaccine

Acetaminophen and Ibuprofen for Prevention of Adverse Reactions Associated with Childhood Immunization

Objective:

To evaluate the literature examining prophylactic use of acetaminophen and ibuprofen for prevention of adverse reactions associated with childhood immunization.

Data Sources:

Articles were identified via MEDLINE/PubMed/EMBASE (1966–March 2007) using the following key terms: vaccination, immunization, diphtheria–tetanus toxoids–whole pertussis (DTwP), diphtheria tetan us–toxoid. whole pertussis, diphtheria-tetanus toxoids–acellular pertussis (DTaP), acellular pertussis, Haemophilus influenzae type B, inactivated poliovirus, pneumococcal 7-valent conjugate, measles, mumps, rubella, meningococcal C-conjugate, varicella zoster, hepatitis B, influenza, pneumococcal polysaccharide, adverse reactions, analgesics, antipyretics, acetaminophen, ibuprofen, infant, and child.

Study Selection and Data Extraction:

No limitations were placed on article selection.

Data Synthesis:

Five articles examining the effects of prophylactic acetaminophen or ibuprofen for adverse effects associated with either DTaP or DTwP vaccine were retrieved. In one randomized controlled trial of children aged 4–6 years given DTaP, no effect of prophylactic acetaminophen 15 mg/kg/dose, up to 450 mg, or ibuprofen 10 mg/kg/dose, up to 300 mg, was found on the incidence of fever, redness, pain, swelling, or itching. In 3 randomized studies of DTwP, either acetaminophen 10–15 mg/kg/dose or ibuprofen 20 mg/kg/24 hours, given in 3 equal doses before or at the time of immunization and every 4–8 hours thereafter for 12 or more hours, reduced fever, pain, fussiness, and local redness in infants 2–7 months of age compared with placebo. Results were not duplicated in older infants/children. No studies investigated use of prophylactic acetaminophen or ibuprofen for any other vaccine.

Conclusions:

Use of prophylactic acetaminophen and ibuprofen may reduce the incidence of adverse reactions in young infants receiving DTwP vaccine; however, DTwP has been replaced with DTaP, and no benefits have been demonstrated for this vaccine when evaluated in children aged 4–6 years, or with any other vaccine currently in use. Thus, neither drug can be recommended prophylactically to prevent vaccine-associated adverse reactions. Individuals at high risk for seizures may, however, warrant special consideration.

Which strategy for pertussis vaccination today?

Pertussis (whooping cough) remains an epidemic disease responsible for infant and child morbidity and mortality, and is perceived as a serious public health problem. Since the widespread use of whole-cell pertussis vaccines in the 1940s, vaccination programs have varied greatly between countries. National specificity is a function of several factors. The most important are: vaccine efficacy and tolerability;vaccine coverage and distribution; and vaccine acceptance by parents and professionals. During the 1970s, Sweden, England, Wales and Japan provided contrasting examples of the attitude of health authorities to the use of whole-cell vaccines. The increase in pertussis incidence was noted as a consequence of active opposition to this vaccine. The re-emergence of pertussis in the 1990s, in countries with high vaccination coverage and increased incidence of disease in individuals >15 years and <6 months of age, has drawn attention to the role of booster doses of pertussis vaccines and their introduction into regular vaccination programs. The use of acellular vaccines for booster doses for adolescents and adults would seem unambiguous because of their decreased reactogenicity, although the exact schedule has yet to be established. The choice between the two kinds of vaccines is more difficult for primary courses, where safety and efficacy profiles are similar, and the attitude towards acellular vaccines varies from country to country. In this case, the strategy adopted results from the national history of pertussis infection and from the quality of the available whole-cell vaccine. Two contrasting examples are the US, where acellular vaccines were licensed for the primary series in the 1990s, and the UK, where whole-cell vaccines are exclusively used for primary immunization. The changing epidemiology of pertussis, and its local diversification, would suggest that at present it is difficult to define a single worldwide strategy with only one kind of vaccine and one schedule. In order to control pertussis incidence, each country should continue to determine the best national vaccination program established in very close relation to the past and present epidemiological situation and available healthcare resources.

An economic evaluation of universal pertussis vaccination in Italy

An economic evaluation was performed of universal acellular pertussis vaccination in Italy, where until recently the overall coverage of pertussis vaccination was estimated at 50%. Over the last two years coverage seems to have increased rapidly. By means of a mathematical simulation model, the consequences of pertussis vaccination in terms of both health effects and economic costs were calculated for a single birth cohort followed for 6 years. Incremental analyses were performed for each additional 10% increase in coverage from 50-90%. The results indicate that a 50% coverage rate of pertussis vaccination in Italy was not optimal on the basis of cost-effectiveness and cost-benefit considerations. Additional increases in coverage were found to yield extra health gains at modest net costs or even potential net savings to the health care sector. For example, an increase in coverage to 90% would yield direct net savings of US$42 per extra vaccinee in comparison to a situation of 50% coverage. The total net savings for this strategy would be well over US$100 per additional vaccinee. In the sensitivity analysis, the positive relationship between incremental coverage and incremental efficiency remained unchanged.

Economic evaluation of pertussis prevention by whole-cell and acellular vaccine in Germany

Acellular pertussis vaccines are less reactogenic than whole cell pertussis vaccines, but they are also more expensive. Based on simulation models, we compared the costs and effects of three alternative pertussis vaccination strategies in German children to "no prevention": (1) vaccination with whole-cell vaccine at 45% coverage (vaccine efficacy 90%), (2) vaccination with acellular vaccine at 45% coverage (vaccine efficacy 85%), and (3) vaccination with acellular vaccine at 90% coverage. In the two low coverage scenarios expected annual savings in direct medical costs through prevention of disease were larger for whole-cell than for acellular vaccination (252 vs 216 million DM, respectively). Direct costs for treating the more important adverse events induced by whole-cell vaccination (16.9 million DM annually) did not outweigh the higher direct costs of pertussis infections not prevented with the acellular vaccine and the higher price of the acellular vaccine. However, vaccination with acellular pertussis vaccine rapidly becomes as cost saving as vaccination with whole-cell vaccine as soon as vaccination coverage can be raised from 45% to 52.5% with acellular vaccine. Acellular vaccination is also the superior alternative when considering indirect cost savings resulting from reduction in work-loss due to adverse events.

CONCLUSION

In our simulations, the most cost-effective pertussis prevention strategy was the use of an effective whole-cell vaccine with a high coverage rate. Introduction of the more expensive acellular pertussis vaccines becomes cost saving if at least a 7.5% increase in coverage is achieved. If also non-medical indirect costs to parents resulting from vaccine associated side-effects are accounted for, acellular vaccines may be more cost-effective also in countries with already high whole-cell vaccine coverage.

Rapid, sensitive and specific diagnosis of Bordetella pertussis using the polymerase chain reaction

Use of a repetitive DNA sequence of Bordetella pertussis allowed successful detection of the organism by the polymerase chain reaction (PCR). The method was highly sensitive, being able to detect B. pertussis in specimens containing only a few cells. It was also highly specific, with no amplification of specimens containing other organisms, for example Haemophilus influenzae or Neisseria, being observed. A diagnosis could be made within 1 day. The PCR assay was also evaluated in clinical specimens. Among 47 nasopharyngeal specimens obtained from 24 patients with laboratory-confirmed pertussis, 27 were positive by PCR and 19 by culture. In particular, all three bronchial aspirates from one patient with pertussis were positive by PCR, but only one showed positive on culture. Eleven specimens from parapertussis patients and 65 specimens from patients without pertussis tested negative. It was concluded that this newly developed PCR method for the diagnosis of pertussis was more rapid and sensitive than the usual culture method. Polymerase chain reaction could have a major impact on the treatment and control of this infection and would be a useful tool for studying the pathogenesis of B. pertussis infection.

Outbreak of pertussis in highly immunized adolescents and its secondary spread to their families

An outbreak of pertussis was recognized in a highly immunized sixth-grade class of schoolchildren. Among 43 children aged 11-12 years in the class, 38 had been immunized with three doses or more of DTP containing whole-cell pertussis vaccine, two with two doses of DTP and three children were unimmunized. The last DTP vaccines had been given 6-10 years before the outbreak. A total of eight children with pertussis suffering paroxysmal coughing attacks for 3 weeks or more were identified, seven being fully immunized and one unimmunized. Among the eight cases, two were confirmed by both culture and serology and one by serology alone. The attack rate in fully immunized children was 18.4% (7/38). Secondary spread of pertussis was identified in five of the households from which the eight patients originated. A total of six cases of pertussis from these five households were identified, and two of these were culture-confirmed. These observations suggest that vaccine-induced immunity weakens considerably 6-10 years after vaccination, and that booster immunization with DTP instead of DT is therefore recommended for the control of pertussis.

Safety and immunogenicity of acellular diphtheria-tetanus-pertussis and Haemophilus conjugate vaccines given in combination or at separate injection sites

This prospective, double-blind, randomized trial compared the immunogenicity and reactogenicity of acellular diphtheria-tetanus-pertussis vaccine and Haemophilus influenzae type b conjugate vaccine-diphtheria toxoid conjugate, given at separate injection sites or at a single site, in 79 children 18 months of age who had received three prior immunizing doses of whole-cell diphtheria-tetanus-pertussis vaccine. No significant differences were observed.

Safety and immunogenicity of hydrogen peroxide-inactivated pertussis toxoid in 18-month-old children

The immunogenicity and adverse effects of an acellular pertussis vaccine consisting of a purified pertussis toxin inactivated with hydrogen peroxide (PTxd) was evaluated. Children aged 15 to 30 months were injected with 10 (n = 33) or 50 micrograms (n = 34) of PTxd or with diphtheria and tetanus toxoids and whole cell pertussis vaccine (DTP) (n = 34). All children had previously received three doses of DTP during infancy. Both dosages of PTxd induced higher IgG antibody (p less than 0.05 for 10 micrograms dose and p less than 0.01 for 50 micrograms dose) and pertussis antitoxin responses (p less than 0.01 for 50 micrograms dose) than DTP. The 50 micrograms dose gave slightly higher (though not significantly) antibody responses than the 10 micrograms dose of PTxd. None of the vaccines induced detectable IgM or IgA antibody responses to pertussis toxin. At 24 h, local reactions occurred in none of the children injected with 10 micrograms PTxd, 12% with 50 micrograms PTxd and 78% with DTP. Fever at 24 h occurred in 13% after 10 micrograms PTxd, in none after 50 micrograms PTxd and in 53% after DTP. Recipients of DTP, but not of PTxd, had significant increases in neutrophils and decreases in lymphocytes and haematocrit at 24 h (all p less than 0.05). None of the groups showed changes in blood glucose at 24 h. PTxd induced pertussis toxin antibody levels similar to those observed in patients convalescing from natural pertussis. This acellular pertussis vaccine deserves further evaluation for safety and immunogenicity in infants and for efficacy in preventing pertussis.

Immunoglobulin A antibodies to pertussis toxin and filamentous hemagglutinin in saliva from patients with pertussis

Immunoglobulin A (IgA) antibodies against pertussis toxin (PT) and filamentous hemagglutinin (FHA) in 181 saliva samples obtained during various stages of pertussis from 112 patients were determined. Saliva samples obtained within 5 days after the onset of symptoms did not have detectable IgA antibodies against either of the two antigens. Of the samples obtained between 6 and 50 days after the onset of symptoms, 72% had antibodies against FHA but only 40% had antibodies against PT. With few exceptions, saliva samples obtained more than 50 days after the onset of symptoms contained antibodies against both antigens. In the 59 patients from whom paired saliva samples were obtained at intervals of 2 to 5 weeks, a significant increase in the geometric mean FHA antibody titers but not PT antibody titers occurred. However, increases that were fourfold or greater were observed against FHA in only 19 patients and against PT in 14 patients. Thus, IgA antibodies against FHA and PT in saliva develop during pertussis, and the importance of secretory IgA antibodies for protection against infection and disease should be investigated. Determination of these antibodies in paired saliva samples is, however, of little value for the laboratory diagnosis of pertussis.

Pertussis vaccines

Concern over adverse reactions temporally associated with whole cell pertussis vaccine and advances in the understanding of the Bordetella pertussis organism have led to a new generation of more purified acellular vaccines. The biology of the pertussis organism, epidemiology of disease, vaccine development over the decades, and vaccine efficacy and adverse reaction data from whole cell and acellular vaccine trials are presented. Questions that remain to be answered before acellular vaccine replaces conventional vaccine are defined, and future studies addressing these questions are proposed.

Immunogenicity and safety of a pertussis vaccine composed of pertussis toxin inactivated by hydrogen peroxide, in 18- to 23-month-old children

A new pertussis vaccine, composed of purified pertussis toxin inactivated by hydrogen peroxide and adsorbed onto aluminum hydroxide (NICHD-Ptxd), was injected into 60 children aged 18 to 23 months without a history of pertussis or pertussis vaccination. Two doses of toxoid, 10 and 50 micrograms, were used. Two injections, given 8 to 12 weeks apart, elicited increases in serum levels of antitoxin and IgG antibodies in 56 children who had no detectable antitoxin (less than 5 units) before vaccination. Four children with detectable antitoxin (greater than or equal to 5 units) before the first vaccination had pronounced antibody increases after the first dose. After the second dose, the geometric mean antitoxin concentration was 29 units with the 50 micrograms dosage and 10 units with the 10 micrograms dosage (p less than 0.001). Serum antibody levels elicited by two injections of 50 micrograms were similar to those in patients convalescing from pertussis. A third injection given to seven children 9 to 10 months after the second injection gave a booster response, with high levels of antitoxin (160 to 1280 units) and of IgG antibodies. With few exceptions the antibody response was restricted to the IgG class. Transient local reactions greater than or equal to 2 cm in diameter occurred in 14% of the children after the first dose and in 44% after the second and third doses. Moderate fever was recorded after 6% of all injections. There were no changes in peripheral blood leukocyte counts or fasting blood glucose levels measured before and 24 hours after the first injection. We conclude that NICHD-Ptxd is immunogenic in children. No serious adverse effects were noted.

Adverse reactions and antibody response to an acellular pertussis toxoid vaccine in adult volunteers

A monovalent pertussis toxoid vaccine (JNIH-7, Biken, Japan) was evaluated for reactogenicity and immunogenicity in 20 healthy adults (phase 1 study). Fever of greater than or equal to 38 degrees C was recorded in 2/20; local reactions started in 2/20 on day 1 (early onset) and in 3/20 on day 7 (late onset). All 15/15 subjects tested showed a significant antibody response to pertussis toxin by neutralization or enzyme-linked immunosorbent assay. Significantly elevated antibodies were still detected in 12/13 subjects 32 months after the single subcutaneous dose of vaccine.

Clinical, metabolic, and antibody responses of adult volunteers to an investigational vaccine composed of pertussis toxin inactivated by hydrogen peroxide

A toxoid vaccine, composed of purified pertussis toxin inactivated with H2O2 (NICHD-Ptxd), was developed on the basis of evidence that serum neutralizing antibodies (antitoxin) would confer immunity to pertussis. In vivo and in vitro assays of NICHD-Ptxd showed only trace or nondetectable levels of pyrogenic, adenosine diphosphate-ribosyltransferase, binding and pharmacologic activities. Nevertheless, about 40% of the antigenicity of pertussis toxin was retained. Adult volunteers were injected, two times 6 weeks apart, with either 10 (n = 21), 50 (n = 25), or 75 (n = 30) micrograms/dose of one lot, Ptx-06, adsorbed onto AI(OH)3. Neither fever nor changes in the levels of leukocytes, lymphocytes, fasting blood glucose, or insulin were observed in the volunteers. The optimal immunizing dose, 50 micrograms, induced levels of antitoxin (geometric mean (GM) 302 U) comparable to those found in eight adults convalescent from pertussis (GM 269 U) and greater than those found in 18-month-old children after their fourth dose of diphtheria and tetanus toxoids and pertussis vaccine (GM 20.0 U, p less than 0.001). These data indicate that NICHD-Ptxd is safe and immunogenic in adults, and they justify its evaluation in infants and children.

Acellular pertussis vaccines: evaluation of reversion in a nude mouse model

An animal model has been developed to assess the safety of acellular pertussis vaccines in terms of reversion to toxicity. Adsorbed pertussis toxoid preparations, alone or combined in a DTP formulation, were administered to nude mice intraperitoneally. In parallel, groups of positive and negative control mice received pertussis toxin and buffer, respectively. The circulating white blood cells of the animals were monitored for 28 days. Mice immunized with glutaraldehyde toxoid preparations did not develop a lymphocytosis during the observation period, whereas mice immunized with an experimental formalin pertussis toxoid vaccine exhibited a high lymphocytosis six days after vaccine administration, demonstrating, in this model, a reversion of the toxoid. The nude mouse model thus appears to reveal the in-vivo reversion of pertussis toxoids and could be included in the quality control panel for the assessment of the safety of acellular pertussis vaccine.

Protective effectiveness of an endotoxin-depleted pertussis vaccine

Pertussis vaccine depleted of endotoxin by the polymyxin-Sepharose affinity chromatography method was tested for toxic activity and protective effectiveness in mice. Preparations containing 1000-fold and 1 000 000-fold less endotoxin fulfilled the established experimental criteria for freedom from toxicity. A fourfold concentrate of the former demonstrated a protection rate only 10% less than that of standard, untreated pertussis vaccine.