Search

Premature infants are at greater risk of infections in part because of impaired functioning of external barriers, innate and adaptive systems. For similar immunological reasons, diminished responses to particular vaccines have also been reported. This study, utilising a prospective, pragmatic case series approach was designed to show non-inferiority of antibody response in premature infants to diphtheria, tetanus, Haemophilus influenzae type b conjugate (Hib), meningococcal C conjugate (MenC) and pneumococcal conjugate (PnC) vaccines between immunization in a routine clinical situation rather than a vaccine trial. A secondary objective was to determine the effect of gestational age on antibody response to these vaccines. The case series comprised 131 infants born at ≤ 32 weeks gestation and managed on the Special Care Baby Unit (SCBU) of a District General Hospital in Stockport, UK. For diphtheria and tetanus, 98.3% and 100% of premature infants respectively developed a minimum protective antibody response; 86.6% were protected against Men C. However, only 67.8% preterm infants achieved anti-polyribosylribitolphosphate (PRP) antibodies >0.15μg against Hib, with only 34.7% having a level ≥1.0μg, and responses to the different pneumococcal serogroups ranged from 67.5% against serotype 6B to 92.5% against serogroup 19F. In comparison to term infants, preterm infants were less likely to achieve protective levels against MenC and Hib: there were no significant differences in the proportions of infants protected against diphtheria and tetanus. Protection was inferior to expected based on published premature infant clinical trial data for Hib and particular pneumococcal serotypes; data for Men C were also lower than expected.

Against a background of new developments and updated clinical guidelines, health care professionals (HCPs) administering childhood and adolescent immunizations require access to expert advice and support when appropriate. The clinical records of all pediatric referrals seen at a UK-based facility-the Stockport Specialist Immunization Clinic (SS IC)-between 01/10/2006 and 31/03/2007 were reviewed to determine the stated reason(s) for referral to a specialist immunization service and the outcome of that process. During the 6 month audit period, 430 case notes were identified and 410 (95%) were audited. Reasons for referral were primarily due to the medical condition of the child [118/410 (29%)], the child having experienced a previous vaccine adverse event [86/410 (21%)], or preterm birth of the child [86/410 (21%)]. The majority of referrals were from primary care [234/410 (57%)]. A total of 351 (85.6%) cases were categorized as appropriate referrals and 36 (11.6%) and 23 (5.6%) were categorized as inappropriate and equivocal, respectively. Four hundred and eight children completed a primary program; for two children the parents declined the advice offered. National data show that a small number of children remain susceptible to vaccine preventable diseases because they fail to access or complete immunization programs through their General Practitioner (GP) and this may be in part because the HCP is unsure about vaccine indications/contra-indications. Clearly a number of referring HCP s in this audit had some level of uncertainty when immunizing children with a pre-existing medical condition or a previous history of vaccine associated AEFI in the child/family, and this may be indicative of a more general problem among HCPs. A consistent approach to providing expert advice and support to primary care professionals in the UK would therefore be expected to make a significant impact on the immunization service by building confidence for parents/guardian, professionals and organizations involved in delivering it. The authors recommend a dedicated specialist immunization clinical service be considered as one approach to achieving this.

Asplenic individuals are at increased risk of infection with Streptococcus pneumoniae. The immune response to pneumococcal conjugate vaccine has not been investigated in this clinical risk group. We investigated immune responses to pneumococcal vaccination in asplenic individuals. Eligible subjects aged > or =4 years received one dose 7-valent pneumococcal conjugate vaccine (PCV7) and, if no prior 23-valent polysaccharide vaccine (PPV23) had been received within previous 5 years, one dose was given 6 months following PCV7. Pre- and post-vaccination blood samples were taken. Pneumococcal serotype-specific IgG levels were determined for 9 serotypes; the 7 in PCV7 plus serotypes1 and by standardized ELISA. One hundred and eleven asplenic individuals were recruited [median age 54.8 years, (18.1-81.8)]. Median age at splenectomy was 29.6 years (3.6-78.3); 108 (97.3%) individuals had previously received PPV23. Compliance with UK recommendations on immunization and prophylaxis in this group was poor, 91 (82%) subjects had received Haemophilus influenzae type b conjugate vaccine and only 68 (62%) had received meningococcal serogroup C conjugate vaccine. In total 61 (55%) subjects were taking antibiotic prophylaxis and 12 subjects had reported previous invasive pneumococcal disease, five episodes of which occurred post-splenectomy. High serotype-specific IgG concentrations were observed pre-PCV7, with significant increases (p < 0.01) in geometric mean concentrations pre- to post-PCV7 for the PCV7 serotypes. Post-PCV7, between 27% (serotype 14) and 69% (serotype 23F) of subjects had a > or =2-fold rise in IgG. Pre-PCV7, the percentage of individuals with levels > or =0.35 microg/mL ranged between 77% (serotype 4) and 97% (serotypes 14, 19F), whilst post-PCV7 this was 90% (serotype 6B) and 99% (serotype 14). No significant increases were observed post-PPV23. Asplenic individuals responded well to PCV7, though protective levels were demonstrated pre-PCV7 in majority of participants due to prior PPV23. Although immunogenic, there is insufficient evidence here to recommend routine PCV7 immunization over PPV23 immunization in adult asplenic individuals.

This was an observational study of non-responsive HCWs who were referred to Stockport Specialist Immunisation Clinic (SSIC) between 1(st) January 2003 and 31(st) May 2006. Anti-HBs titres were determined 4-6 weeks after each intradermal recombinant vaccine (IDRV). Median anti-HBs titres were compared using the exact Wilcoxon rank sum test. In total, 23 eligible non-responding HCWs were identified. Protective anti-HBs titres (> or =10 mlU/ml) were induced in the majority of non-responders [21/23 (91.3%)] following two doses of IDRVs. HCWs who responded to the 1(st) IDRV with anti-HBs levels > or =10 mlU/ml were significantly younger and received their 1(st) IDRV more than six months after the last IM dose. Two HCWs (41 and 45 year old females) anti-HBs titres remained below 10 mlU/ml even after a 3(rd) dose. Anti-HBs titres were available for 40% (9/23) of the HCWs six or more months after the last maximum anti-HBs titres were achieved. None of the nine HCWs anti-HBs titres declined to less than 10 mlU/ml six or more months after the last maximum anti-HBs titres were achieved. However, a larger study with long-term follow-up is needed to determine the duration of protection following IDRV. HCWs with anti-HBs titres <10 mlU/ml after two full courses of intramuscular recombinant vaccine (IMRV) should be offered two doses of IDRVs followed by assessment of anti-HBs titres one to four months after the second dose in order to identify persistent non-responders. No significant adverse events were noted with IDRV being well tolerated and acceptable to HCWs.