Pertussis Infection in Fully Vaccinated

Children in Day-Care Centers, Israel
Isaac Srugo,* Daniel Benilevi,* Ralph Madeb,* Sara Shapiro,†Tamy Shohat,‡ Eli Somekh,§ Yossi Rimmar,* Vladimir Gershtein,† Rosa Gershtein,* Esther Marva,¶ and Nitza Lahat† *Department of Clinical Microbiology, Bnai Zion Medical Center, Haifa, Israel; †Serology Laboratory, Carmel Medical Center, Haifa, Israel; ‡Israel Center for Disease Control, Tel Aviv, Israel; §Wolfson Medical Center,
Tel Aviv, Israel; ¶Public Health Laboratories, Jerusalem, Israel
Address for correspondence: Isaac Srugo, Department of Clinical Microbiology, Bnai Zion Medical Center, POB 4940, Haifa, Israel 31048; Fax: 972-4-835-9614; e-mail: srugoi@tx.technion.ac.il.

We tested 46 fully vaccinated children in two day-care centers in Israel who were exposed to a fatal case of pertussis infection. Only two of five children who tested positive for Bordetella pertussis met the World Health Organization’s case definition for pertussis. Vaccinated children may be asymptomatic reservoirs for infection. Vol. 6, No. 5, September–October 2000 Emerging Infectious Diseases 527 Dispatches Figure. Timeline of pertussis infection in children in two day-care centers, Israel. the same house, reported a mild respiratory illness without paroxysmal cough. None of the family members had a whooping episode, cyanosis, or pneumonia (Figure). All the children in the day-care centers had been immunized in infancy with all four doses of Pasteur diphtheria-tetanus toxoid pertussis (DTP) vaccine, which includes a booster dose at 12 months of age. The Pasteur vaccine contains 1 immunization dose (ID) of purified diphtheria toxoid, 1 ID of purified tetanus toxoid, and >4 IU of B. pertussis. All family members of the infant were also fully vaccinated with four doses of DTP. The infant had received only the first dose of vaccine at 2 months of age.

The five family members of the infant and the 46 children in the two day-care centers were tested for B. pertussis. Two nasopharyngeal specimens were taken with Dacron swabs (Medical Wire, MEDECO, Corsham, UK); one specimen was used for culture and the other for polymerase chain reaction (PCR) testing. The culture specimen was immediately spread on charcoal agar plates (Hy Labs, Rehovot, Israel), which were incubated at 37°C for 14 days. Serum samples were also taken from every study participant for specific testing for immunoglobulin (Ig) M, IgA, and IgG antibodies to B. pertussis by an enzyme immunoassay (EIA) with whole-cell antigens (Panbio, East Brisbane, Australia) (12). Primers for the repeated insertion sequences were used in a semi-nested PCR assay (13-14). The upstream primer sequence gATTCAATA ggTTgTATgCATggTT and downstream primer AATTgCTggACCAT TCgAgTCgACG were used in the first PCR, which included 5 µL sample
DNA, reaction buffer (10 mM Tris-HCl, 50 mM KCl, 1.5 mM MgCl2, 0.1% Triton X-100), 1 µM of each primer, 200 µM deoxynucleotide triphosphate, and 1 U Taq polymerase (Boehringer Mannheim, Germany) in a 25-µL volume (14). Statistical analysis was performed by the twotailed Fisher’s exact test.

A person with positive PCR results was considered to have B. pertussis colonization of the nasopharynx. A person with positive IgM serum antibodies was considered to have had a recent infection. There were no culture-positive results, and nasopharyngeal aspirates were not available
from the infant. Positivity by PCR or IgM did not indicate presence of symptoms. Information on clinical symptoms was obtained from each person by a detailed questionnaire. The children in the day-care centers were followed clinically for 8 weeks after laboratory testing. All family members had been treated with erythromycin before testing, but no antibiotics were administered to the children in
the day-care centers. Eleven percent of the children in the two daycare centers were PCR positive, indicating nasopharyngeal colonization: 4 (25%) of the 16 5- to 6-year-old and 1 (3%) of the 30 2- to 3-year-old children (p <.05). Nine (55%) 5- to 6-year-old children were positive for serum IgM antibodies, and 4 (25%) were IgA positive. Three (10%) of the 2- to 3-year-old children were IgM positive, and 1 (3%) had IgA antibodies. Nasopharyngeal colonization was found more frequently in the 5- to 6-year-old than in the 2- to 3-year-old children (4/16 vs. 1/30, p <.05). This trend was also
constant with IgM and IgA serum antibodies (9/16 vs. 3/30, p <.001 and 4/16 vs. 0/30, p <.01, respectively). In the index family, four of five members were positive by PCR, including all three siblings of the infant and the 18-year-old aunt. The 35-year-old mother, who was treated with erythromycin before testing, was negative by PCR. All five family members, including the mother, had high levels of IgM antibodies, indicating recent infection. The 4-month-old infant was seronegative for all subclasses of Ig antibodies to B. pertussis. No cultures were grown from the three groups.
According to a modified World Health Organization (WHO) case definition, two of the five children colonized with B. pertussis in the two day-care centers had the typical course of pertussis infection, with 3 weeks of paroxysmal cough (Table) (1). The other three children who were positive by PCR had only a mild, nonspecific cough during follow-up.528 Emerging Infectious Diseases Vol. 6, No. 5, September–October 2000 Dispatches
Conclusions

The effects of whole-cell pertussis vaccine wane after 5 to 10 years, and infection in a vaccinated person causes nonspecific symptoms (3-7). Vaccinated adolescents and adults may serve as reservoirs for silent infection and become potential transmitters to unprotected infants (3-11). The whole-cell vaccine for pertussis is protective only against clinical disease, not against infection (15-17). Therefore, even young, recently vaccinated children may serve as reservoirs and potential transmitters of infection. We used PCR, EIA, and culture to confirm B. pertussis infection in two highly vaccinated groups of children in two day-care centers. Three (10%) of 30 2- to 3-year-old children were seropositive for recent infection; one had nasopharyngeal colonization and a clinical
illness that met the modified WHO case definition. In the day-care center for the 5- to 6- year-old group, 9 (55%) of 16 children were IgM positive, 4 (25%) of whom had nasopharyngeal colonization. Of these four children, three had nonspecific cough, and only one met the modified WHO definition for pertussis. None of the children in our study, including those who met the WHO definition, had been examined by a physician before our investigation. Children who were seropositive and remained both asymptomatic and PCR negative probably had sufficient immunity from vaccines
or natural boosters to protect them against persistent colonization and clinical disease. Their seropositivity could not be due to vaccine because the children were tested more than a year after
having been vaccinated. Yet not all the children were protected from infection and from colonization
with the bacteria. Whether a child who is serologically or PCR positive for pertussis and is clinically asymptomatic is a potential transmitter of infection has not been established. What is certain, however, is that vaccine-induced immunity against infection does not persist throughout adulthood. In France, booster vaccinations have been recommended for adolescents and teenagers (18). We found that immunity does not even persist into early childhood in some cases. We also observed that DPT vaccine does not fully protect children against the level of clinical disease defined by WHO. Our results indicate that children ages 5-6 years and possibly younger, ages 2-3 years, play a role as silent reservoirs in the transmission of pertussis in the community. More studies are needed to find the immunologic basis of protection against infection and colonization and thus an effective way to
eradicate pertussis. Dr. Srugo is a senior lecturer and director of the Clinical Microbiology and Pediatric Infectious Disease unit at the Bnai Zion Medical Center, Haifa, Israel.
References
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7. Yaari E, Yafe-Zimerman Y, Scwartz SB, Slater PE, Shvartzman P, Andoren N, et al. Clinical manifestations of Bordetella pertussis infection in immunized children and young adults. Chest 1999;115:1254-8.

8. Aoyama T. Takeuchi Y, Goto A, Iwai H, Murase Y, Iwata T. Pertussis in adults. Am J Dis Child 1992; 146:163-6.
Table. Clinical and laboratory profiles of children positive for Bordetella pertussis by polymerase chain reaction (PCR) in Israel
Day-Care Clinical
Center PCR+ IgMa+ IgA+ Culture+ Pertussisb
Ages 2-3
Child 1 Yes Yes No No Yes
Ages 5-6
Child 2 Yes Yes Yes No Yes
Child 3 Yes Yes Yes No Noc
Child 4 Yes Yes Yes No Noc
Child 5 Yes Yes Yes No Noc
aIg = Immunoglobulin.
bParoxysmal cough >3 weeks; modified World Health
Organization case definition (1).
cNonspecific cough during 4 weeks of follow-up.
Vol. 6, No. 5, September–October 2000 Emerging Infectious Diseases 529
Dispatches
9. Cromer BA, Boydos J, Hackell J, Mezzatesta J, Dekker C, Mortimer EA. Unrecognized pertussis infection in adolescents. Am J Dis Child 1993;147:575-7.
10. Nelson JD. The changing of epidemiology of pertussis in young infants: the role of adults as reservoirs of infection. Am J Dis Child 1978;132:371-3.

11. Baron S, Njamkepo E, Grimprel E, Begue P, Desenclos JC, Drucker J, et al. Epidemiology of pertussis in French hospitals in 1993 and 1994: thirty years after a routine vaccination. Pediatr Infect Dis J 1998;17:412-8. 12. He Q, Mertsola J, Soini H, Skurnik M, Ruuskanen O, Viljanen MK. Comparison of polymerase chain reaction with culture and enzyme immunoassay for diagnosis of
pertussis. J Clin Microbiol 1993;31:642-5.
13. He Q, Mertsola I, Soini H, Viljanen MK. Sensitive and specific polymerase chain reaction assays for detection of Bordetella pertussis in nasopharyngeal specimens. J Pediatr 1994;124:421-6.
14. Lichtinghagen R, Diedrich-Glaubitz R, von Horsten B. Identification of Bordetella pertussis in nasopharyngeal swabs using a polymerase chain reaction: evaluation of detection methods. European Journal of Clinical Chemistry and Biochemistry 1994; 32:161-7.
15. Fine PEM, Clarkson JA. The recurrence of whooping cough: possible implications for assessment of vaccine efficacy. Lancet 1982;l:666-9.
16. Long SS, Welkon CJ, Clark JL. Widespread silent transmission of pertussis in families: antibody
correlates of infection and symptomatology. J Infect Dis 1990;161:480-6.
17. Minh NNTM, He Q, Edelman K, Olander RM, Viljanen MK, Arvilommi H, et al. Cell-mediated immune response to antigens of Bordetella pertussis and protection against pertussis in schoolchildren. Pediatr Infect Dis J 1999;18:366-70.
18. Grimprel E, Baron S, Levy-Bruhl D, Garnier JM,
N’jamkepo E, Guiso N, et al. Influence of vaccination coverage on pertussis transmission in France. Lancet 1999;354:1699-700.

Zh Mikrobiol Epidemiol Immunobiol. 1982 May;(5):53-7. Related Articles, Links

[Evaluation of the toxic action of prophylactic and therapeutic preparations on cell cultures of different types and origin. II. The cytotoxic action of adsorbed DPT vaccine and its components on cells of the continuous L132 line]

[Article in Russian]

Kravchenko AT, Sovetova GP, Chebotareva SV.

Different batches of the same preparation manufactured at the same enterprise, or at different enterprises, in accordance with the same manufacturing regulations have been found to be capable of producing a damaging effect of different intensity on the continuous cell culture L132. The titers vary, according to their cytotoxic effect, from 1 : 32 to 1 :2048. The components of B. pertussis antigens and thimerosal solutions have been found to produce the most pronounced cytotoxic effect on the cells. The comparison of the results of the titration of adsorbed DPT vaccine in cell cultures with clinical manifestations has shown correlation between a greater degree of cell damage in vitro and severe local reaction. Therefore, in the process of the quality control of preparations cell cultures provide more sensitive tests than laboratory animals, which is confirmed by our data obtained in revealing the toxic properties of adsorbed DPT vaccine and its components.

PMID: 7102181 [PubMed - indexed for MEDLINE]



Zh Mikrobiol Epidemiol Immunobiol. 1983 Mar;(3):87-92. Related Articles, Links

[Evaluation of the toxic action of prophylactic and therapeutic preparations on cell cultures. III. The detection of toxic properties in medical biological preparations by the degree of cell damage in the L132 continuous cell line]

[Article in Russian]

Kravchenko AT, Dzagurov SG, Chervonskaia GP.

The methods of the quality control of medical biological preparations, including tests on animals, do not ensure the complete absence of toxicity in a final product. The use of the method of "subcultures with the introduced preparation" makes it possible to determine the toxicity of both specific and nonspecific components of vaccines and sera from the number of dead and damaged cells. The toxic action of preparations kills and damages the cells at the site of injection, thus inducing the formation of autoantigens whose effect on the body cannot be predicted. Thus thimerosal, commonly used as preservative, has been found not only to render its primary toxic effect, but also capable of changing the properties of cells. This fact suggests that the use of thimerosal for the preservation of medical biological preparations, especially those intended for children, is inadmissible.

PMID: 6845931 [PubMed - indexed for MEDLINE]

 

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