Effectiveness of oral aciclovir in preventing maternal chickenpox: A comparison with VZIG.

OBJECTIVES: Although often presenting as a self-limiting childhood disease, chickenpox can have serious consequences if acquired in pregnancy. Until April 2022, the UK recommendations were that varicella immunoglobulin (VZIG) should be administered intramuscularly to susceptible pregnant women exposed to chickenpox prior to 20 weeks gestation. Oral aciclovir or VZIG was recommended if exposure occurred at 20+ weeks gestation. Our objective was to compare the effectiveness of oral aciclovir to VZIG in preventing maternal and neonatal chickenpox. METHODS: We identified and followed up 186 pregnant women who were exposed to chickenpox and compared their outcomes. RESULTS: 171/186 (91.9%) of these women received either VZIG or oral aciclovir. Of the 145 women who received VZIG, 53/145 (36.6%) went on to develop chickenpox compared to 8 of the 26 (30.8%) women who received oral aciclovir (p = 0.32). No statistical difference was found between the oral aciclovir and VZIG groups even after controlling for maternal age, gestational stage, type of exposure and IgG titre (adjusted OR:0.83; 95%CI:0.26-2.65; p = 0.75). CONCLUSIONS: These findings support the use of oral aciclovir as first-line prophylaxis in pregnant women exposed to varicella as they suggest its effectiveness at preventing maternal chickenpox is either better or equal to VZIG.

Improving vaccine coverage in adolescence and beyond.

High vaccine coverage is required to ensure population protection, including protection of those that cannot receive vaccines either due to contraindications or age. Despite this, some areas continue to report low vaccine coverage. Reasons for this may vary but can include factors such as difficulties accessing services, conflicting priorities and false contraindications or fear of potential side effects. Population groups with reported low vaccine coverage include pregnant women, adolescents and those aged 70-80 years and eligible to receive the shingles vaccine. The afternoon symposium included presentations from speakers each describing interventions for promoting vaccine uptake in these particular groups. Such interventions may include: • Ensuring effective leadership with clear aims for the delivery and on-going evaluation of the program • Providing health care workers with training and access to factually correct immunization resources • Offering a flexible service with vaccination in venues that are easy to access.

Improving vaccine uptake: an overview.

A task group was formed with the aim to improve the quality of the service offered by ensuring that all children waiting for an appointment for vaccination would be offered one at the earliest opportunity. Children aged between 12 mo-5 y that were not completely immunized for their age were identified and included in a pilot catch-up session. Following evaluation of the pilot session, four further immunization sessions were delivered. A total of 398 children attended the four sessions, representing an improved attendance rate of 39%. Most parents brought their children between 11 am-3 pm and 728 vaccines were administered: 339 MMR; 255 Pre-school boosters; 53 Hib/MenC and 81 PCV. Uptake of MMR vaccine in the PCT at age 24 mo increased by 9% by Q3 2008. For children aged five years, uptake of the first dose of MMR vaccine increased from 91.9% to 94% for the first dose and from 82.3 to 82.5% for the second dose by Q3 2008. This project demonstrates that new ways of delivering immunization sessions can be successfully implemented which can enhance access through the use of alternative venues and subsequently lead to increased vaccine uptake.

Attitudinal and demographic predictors of measles-mumps-rubella vaccine (MMR) uptake during the UK catch-up campaign 2008-09: cross-sectional survey.

BACKGROUND AND OBJECTIVE: Continued suboptimal measles-mumps-rubella (MMR) vaccine uptake has re-established measles epidemic risk, prompting a UK catch-up campaign in 2008-09 for children who missed MMR doses at scheduled age. Predictors of vaccine uptake during catch-ups are poorly understood, however evidence from routine schedule uptake suggests demographics and attitudes may be central. This work explored this hypothesis using a robust evidence-based measure. DESIGN: Cross-sectional self-administered questionnaire with objective behavioural outcome. SETTING AND PARTICIPANTS: 365 UK parents, whose children were aged 5-18 years and had received <2 MMR doses before the 2008-09 UK catch-up started. MAIN OUTCOME MEASURES: Parents' attitudes and demographics, parent-reported receipt of invitation to receive catch-up MMR dose(s), and catch-up MMR uptake according to child's medical record (receipt of MMR doses during year 1 of the catch-up). RESULTS: Perceived social desirability/benefit of MMR uptake (OR = 1.76, 95% CI = 1.09-2.87) and younger child age (OR = 0.78, 95% CI = 0.68-0.89) were the only independent predictors of catch-up MMR uptake in the sample overall. Uptake predictors differed by whether the child had received 0 MMR doses or 1 MMR dose before the catch-up. Receipt of catch-up invitation predicted uptake only in the 0 dose group (OR = 3.45, 95% CI = 1.18-10.05), whilst perceived social desirability/benefit of MMR uptake predicted uptake only in the 1 dose group (OR = 9.61, 95% CI = 2.57-35.97). Attitudes and demographics explained only 28% of MMR uptake in the 0 dose group compared with 61% in the 1 dose group. CONCLUSIONS: Catch-up MMR invitations may effectively move children from 0 to 1 MMR doses (unimmunised to partially immunised), whilst attitudinal interventions highlighting social benefits of MMR may effectively move children from 1 to 2 MMR doses (partially to fully immunised). Older children may be best targeted through school-based programmes. A formal evaluation element should be incorporated into future catch-up campaigns to inform their continuing improvement.

Attitudinal and demographic predictors of measles, mumps and rubella (MMR) vaccine acceptance: development and validation of an evidence-based measurement instrument.

BACKGROUND AND OBJECTIVE: Parents' attitudes toward MMR vaccine and measles, mumps and rubella infections relate to their child's MMR status, therefore improving these attitudes is central to improving current suboptimal MMR uptake. However, no study has yet combined evidence-based, comprehensive and psychometrically validated assessment of these attitudes with reliable objective MMR status data, in order to identify through multivariate analyses the strongest attitudinal predictors of MMR uptake for interventions to target. The present study fills this lacuna by developing and testing a robust evidence-based MMR attitudes measurement instrument. DESIGN: Cross-sectional self-administered postal/telephone questionnaire with objective behavioural outcome. SETTING AND PARTICIPANTS: 535 parents of children aged 5-18 in London and north-west England, UK (response rate 18.1%). Recruitment via Primary Care Trust records, age-stratified purposive sample with suboptimally immunised cases oversampled. MAIN OUTCOME MEASURES: Parents' responses to evidence-based measurement instrument comprising 20 attitude/previous behaviour items (collapsing to 5 scales) and 7 demographic items, and their children's PCT-recorded 5th birthday status for MMR dose 1 (on-time, late or none) and MMR dose 2 (on-time or none). RESULTS: The attitudes measurement instrument was psychometrically robust: content valid, and demonstrating good or acceptable internal consistency (Cronbach's alpha=0.55-0.75 for all scales), test-retest reliability (Pearson's correlation >0.60-0.80, p<0.01 to <0.001 for all scales and 11 individual items), concurrent/construct validity (t-tests for difference between MMR status groups p<0.05 for four scales and thirteen individual items), and predictive/criterion validity (OR=0.66, 95% confidence interval=0.48-0.92 to OR=1.97, 95% CI=1.18-3.31 for three scales and five individual items). Black and minority ethnicity (OR=1.94, 95% CI=1.15-3.30 to OR=4.15, 95% CI=2.40-7.19), positive MMR attitudes (OR=1.63, 95% CI=1.00-2.66 to OR=1.97, 95% CI=1.18-1.31), and positive social attitudes (OR=1.64, 95% CI=1.23-2.40 to OR=1.72, 95% CI=1.13-2.38) independently predicted uptake for both MMR doses. MMR status groups differed most strongly on preference for single measles, mumps and rubella vaccines (6-9% variance in status explained), previous MMR acceptance/rejection (5-9%), and wishing to protect others through vaccinating one's own child (6-8%). CONCLUSIONS: The measurement instrument is robust on multiple validity and reliability dimensions, and is appropriate for use in research and practice as a tool for designing and evaluating interventions. Parents appear to act in line with their attitudes toward MMR vaccine, though attitudes toward measles infection bore little relation to MMR uptake. This study indicates populations and attitudes to be prioritized in MMR uptake improvement interventions.

Referrals to a pediatric immunization service: Findings from a practice-based audit of a UK specialist immunization clinic.

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.

Immune response to pneumococcal conjugate vaccination in asplenic individuals.

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.

Intradermal recombinant hepatitis B vaccination (IDRV) for non-responsive healthcare workers (HCWs).

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.

Immune response to meningococcal serogroup C conjugate vaccine in asplenic individuals.

Asplenic individuals are known to be at increased risk of infection with encapsulated bacteria. Recent United Kingdom recommendations stated that this at-risk group should receive one dose of the meningococcal serogroup C conjugate (MCC) vaccine. However, the immune response of asplenic individuals to MCC vaccine is unknown. The immune response of asplenics (n = 130) to immunization with the MCC vaccine was investigated. Asplenic individuals had a significantly lower geometric mean titer (GMT) (157.8; 95% confidence interval [CI], 94.5 to 263.3) of bactericidal antibody in serum (SBA) than an age-matched control group (n = 48) (1448.2; 95% CI, 751.1 to 2792.0). However, 80% of asplenic individuals achieved the proposed protective SBA titer of > or =8. No differences were observed between the two groups in the serogroup C-specific immunoglobulin G geometric mean concentration. A significant reduction in SBA GMT or the number of responders achieving an SBA titer of > or =8 was observed if the reason for splenectomy was a medical cause or if MCC vaccination occurred <10 years after splenectomy. Individuals (n = 29) who did not achieve an SBA titer of > or =16 were offered a second dose of MCC vaccine. Analysis of the SBA response revealed that 61% (14 of 23) of the individuals who received a second dose achieved a protective titer. In total, 93% of asplenic individuals achieved a titer of > or =8 following MCC vaccination (one or two doses combined). We recommend that, following vaccination of asplenics, either the level of functional antibody should be determined, with a second dose of MCC vaccine offered to nonresponders, or two doses of MCC vaccine should be routinely offered.