Needle size for vaccination procedures in children and adolescents

BACKGROUND

This is an update of a Cochrane Review first published in 2015. The conclusions have not changed.Hypodermic needles of different sizes (gauges and lengths) can be used for vaccination procedures. The gauge (G) refers to the outside diameter of the needle tubing. The higher the gauge number, the smaller the diameter of the needle (e.g. a 23 G needle is 0.6 mm in diameter, whereas a 25 G needle is 0.5 mm in diameter). Many vaccines are recommended for injection into muscle (intramuscularly), although some are delivered subcutaneously (under the skin) and intradermally (into skin). Choosing an appropriate length and gauge of a needle may be important to ensure that a vaccine is delivered to the appropriate site and produces the maximum immune response while causing the least possible harm. Guidelines conflict regarding the sizes of needles that should be used for vaccinating children and adolescents.

OBJECTIVES

To assess the effects of using needles of different sizes for administering vaccines to children and adolescents on vaccine immunogenicity (the ability of the vaccine to elicit an immune response), procedural pain, and other reactogenicity events (adverse events following vaccine administration).

SEARCH METHODS

We updated our searches of CENTRAL, MEDLINE, Embase, and CINAHL to October 2017. We also searched proceedings of vaccine conferences and two trials registers.

SELECTION CRITERIA

Randomised controlled trials evaluating the effects of using hypodermic needles of any gauge or length to administer any type of vaccine to people aged from birth to 24 years.

DATA COLLECTION AND ANALYSIS

Three review authors independently extracted trial data and assessed the risk of bias. We contacted trial authors for additional information. We rated the quality of evidence using the GRADE system.

MAIN RESULTS

We included five trials involving 1350 participants in the original review. The updated review identified no new trials. The evidence from two small trials (one trial including infants and one including adolescents) was insufficient to allow any definitive statements to be made about the effects of the needles evaluated in the trials on vaccine immunogenicity and reactogenicity.The remaining three trials (1135 participants) contributed data to comparisons between 25 G 25 mm, 23 G 25 mm, and 25 G 16 mm needles. These trials included infants predominantly aged from two to six months undergoing intramuscular vaccination in the anterolateral thigh using the World Health Organization (WHO) injection technique (skin stretched flat, needle inserted at a 90° angle and up to the needle hub in healthy infants). The vaccines administered were combination vaccines containing diphtheria, tetanus, and whole-cell pertussis antigens (DTwP). In some trials, the vaccines also contained Haemophilus influenzae type b (DTwP-Hib) and hepatitis B (DTwP-Hib-Hep B) antigen components.Primary outcomesIncidence of vaccine-preventable diseases: No trials reported this outcome.Procedural pain and crying: Using a wider gauge 23 G 25 mm needle may slightly reduce procedural pain (low-quality evidence) and probably leads to a slight reduction in the duration of crying time immediately after vaccination (moderate-quality evidence) compared with a narrower gauge 25 G 25 mm needle (one trial, 320 participants). The effects are probably not large enough to be clinically relevant.Secondary outcomesImmune response: There is probably little or no difference in immune response, defined in terms of the proportion of seroprotected infants, between use of 25 G 25 mm, 23 G 25 mm, or 25 G 16 mm needles to administer a series of three doses of a DTwP-Hib vaccine at ages two, three, and four months (moderate-quality evidence, one trial, numbers of participants in analyses range from 309 to 402. The immune response to the pertussis antigen was not measured).Severe and non-severe local reactions: 25 mm needles (either 25 G or 23 G) probably lead to fewer severe and non-severe local reactions after DTwP-Hib vaccination compared with 25 G 16 mm needles (moderate-quality evidence, one trial, 447 to 458 participants in analyses). We estimate that one fewer infant will experience a severe local reaction (extensive redness and swelling) after the first vaccine dose for every 25 infants vaccinated with the longer rather than the shorter needle (number needed to treat for an additional beneficial outcome (NNTB) with a 25 G 25 mm needle: 25 (95% confidence interval (CI) 15 to 100); NNTB with a 23 G 25 mm needle: 25 (95% CI 17 to 100)). We estimate that one fewer infant will experience a non-severe local reaction (any redness, swelling, tenderness, or hardness (composite outcome)) at 24 hours after the first vaccine dose for every 5 or 6 infants vaccinated with a 25 mm rather than a 16 mm needle (NNTB with a 25 G 25 mm needle: 5 (95% CI 4 to 10); NNTB with a 23 G 25 mm needle: 6 (95% CI 4 to 13)). The results are similar after the second and third vaccine doses.Using a narrow gauge 25 G 25 mm needle may produce a small reduction in the incidence of local reactions after each dose of a DTwP vaccine compared with a wider gauge 23 G 25 mm needle, but the effect estimates are imprecise (low-quality evidence, two trials, 100 to 459 participants in analyses).Systemic reactions: The comparative effects of 23 G 25 mm, 25 G 25 mm, and 25 G 16 mm needles on the incidence of postvaccination fever and other systemic events such as drowsiness, loss of appetite, and vomiting are uncertain due to the very low quality of the evidence.

AUTHORS' CONCLUSIONS

Using 25 mm needles (either 23 G or 25 G) for intramuscular vaccination procedures in the anterolateral thigh of infants using the WHO injection technique probably reduces the occurrence of local reactions while achieving a comparable immune response to 25 G 16 mm needles. These findings are applicable to healthy infants aged two to six months receiving combination DTwP vaccines with a reactogenic whole-cell pertussis antigen component. These vaccines are predominantly used in low- and middle-income countries. The applicability of the findings to vaccines with acellular pertussis components and other vaccines with different reactogenicity profiles is uncertain.

Delivery of immunoreactive antigen using a controllable needle-free jet injector

Intradermal immunization of mice against hepatitis B surface antigen (HBsAg) using a novel real-time controlled jet injector was assessed by comparison with intradermal and subcutaneous injection of antigen using a 27G needle and syringe. Three doses of aluminium-absorbed HBsAg were delivered at 0, 14, and 28days. Antibodies to HBsAg were detected only in mice injected with antigen with antibody levels increasing with secondary injections. Mice vaccinated by intradermal injection using the jet injector or subcutaneous needle injection exhibited comparable immune responses at day 47. Differences in titer observed between intradermal jet injected and needle injected animals reflect differences in the volume of antigen delivered. With the exception of minor bleeding at the injection site in a few animals injected either by jet injection or needle, no adverse events were observed in any of the mice used in the study.

Needle size for vaccination procedures in children and adolescents

BACKGROUND

Hypodermic needles of different sizes (gauges and lengths) can be used for vaccination procedures. The gauge (G) refers to the outside diameter of the needle tubing. The higher the gauge number, the smaller diameter of the needle (eg a 25 G needle is 0.5 mm in diameter and is narrower than a 23 G needle (0.6 mm)). Many vaccines are recommended for injection into muscle (intramuscularly), although some are delivered subcutaneously (under the skin) and intradermally (into skin). Choosing an appropriate length and gauge of a needle may be important to ensure that a vaccine is delivered to the appropriate site and produces the maximum immune response while causing the least possible harm. There are some conflicting guidelines regarding the lengths and gauges of needles that should be used for vaccination procedures in children and adolescents.

OBJECTIVES

To assess the effects of using needles of different lengths and gauges for administering vaccines to children and adolescents on vaccine immunogenicity (the ability of the vaccine to elicit an immune response), procedural pain, and other reactogenicity events (adverse events following vaccine administration).

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (The Cochrane Library 2014, Issue 10), MEDLINE and MEDLINE in Progress via Ovid (1947 to November 2014), EMBASE via Ovid (1974 to November 2014), and CINAHL via EBSCOhost (1982 to November 2014). We also searched reference lists of articles and textbooks, the proceedings of vaccine conferences, and three clinical trial registers.

SELECTION CRITERIA

Randomised controlled trials evaluating the effects of using hypodermic needles of any gauge or length to administer any type of vaccine to people aged from birth to 24 years.

DATA COLLECTION AND ANALYSIS

Three review authors independently extracted trial data and assessed the risk of bias. We contacted trial authors for additional information. We rated the quality of evidence using the GRADE system.

MAIN RESULTS

We included five trials involving 1350 participants. Data for the primary review outcomes were either absent (for the incidence of vaccine-preventable diseases) or limited (for procedural pain and crying). The available evidence was compromised by the use of surrogate immunogenicity outcomes, incomplete blinding of outcome assessors, and imprecision for some outcomes. The evidence from two small trials was insufficient to allow any confident statements to be made about the effects of the needles evaluated in the trials on vaccine immunogenicity and reactogenicity.The remaining three trials (1135 participants) contributed data to comparisons between 25 G 25 mm, 23 G 25 mm, and 25 G 16 mm needles. These trials involved infants predominantly aged two to six months undergoing intramuscular vaccination in the anterolateral thigh using the World Health Organization (WHO) injection technique (skin stretched flat, needle inserted at a 90° angle and up to the needle hub in healthy infants). The vaccines administered were combination vaccines containing diphtheria, tetanus, and whole-cell pertussis antigens (DTwP). In some trials, the vaccines also contained Haemophilus influenzae type b (DTwP-Hib) and hepatitis B (DTwP-Hib-HepB) antigen components.We found moderate quality evidence from one trial that there is probably little or no difference in immune response, defined in terms of the proportion of seroprotected infants, between using 25 G 25 mm, 23 G 25 mm, or 25 G 16 mm needles to administer a series of three doses of a DTwP-Hib vaccine at ages two, three, and four months (numbers of participants in analyses range from 309 to 402. Immune response to pertussis antigen not measured).25 mm needles (either 23 G or 25 G) probably lead to fewer severe local reactions (extensive redness and swelling) and fewer non-severe local reactions (any redness, swelling, tenderness or hardness (composite outcome)) after DTwP-Hib vaccination compared with 25 G 16 mm needles. We estimate that one fewer infant will experience a severe local reaction after the first vaccine dose for every 25 infants vaccinated with the longer rather than the shorter needle (number needed to treat (NNT) 25 (95% confidence interval (CI) 15 to 100)). We estimate that one fewer infant will experience a non-severe local reaction at 24 hours after the first, second, and third vaccine doses for every five to eight infants vaccinated with the longer rather than the shorter needle (NNTs range from 5 (95% CI 4 to 10) to 8 (95% CI 5 to 34)) (moderate quality evidence, one trial for first and second doses, two trials for third dose, numbers of participants in analyses range from 413 to 528).Using a wider gauge needle (23 G 25 mm) may slightly reduce procedural pain (low quality evidence) and probably leads to a slight reduction in the duration of crying time immediately after vaccination (moderate quality evidence) compared with a narrower gauge (25 G 25 mm) needle (one trial, 320 participants). The effects are probably not large enough to be of any clinical relevance. The 25 G 25 mm needle may produce a small reduction in the incidence of local reactions after each dose of a DTwP vaccine compared with the 23 G 25 mm needle, but the effect estimates are imprecise (low quality evidence, two trials, numbers of participants in analyses range from 100 to 459).The comparative effects of 23 G 25 mm, 25 G 25 mm, and 25 G 16 mm needles on the incidence of post-vaccination fever, persistent inconsolable crying, and other systemic events such as drowsiness, loss of appetite, and vomiting are uncertain due to the very low quality of the evidence.

AUTHORS' CONCLUSIONS

Using 25 mm needles (either 23 G or 25 G) for intramuscular vaccination procedures in the anterolateral thigh of infants using the WHO injection technique probably reduces the occurrence of local reactions while achieving a comparable immune response to 25 G 16 mm needles. These findings are applicable to healthy infants aged two to six months receiving combination DTwP vaccines with a reactogenic whole-cell pertussis antigen component. These vaccines are predominantly used in developing countries. The applicability of the findings to vaccines with acellular pertussis components and other vaccines with different reactogenicity profiles is uncertain.

Transcutaneous immunization using a dissolving microneedle array protects against tetanus, diphtheria, malaria, and influenza

Transcutaneous immunization (TCI) is an attractive alternative vaccination route compared to the commonly used injection systems. We previously developed a dissolving microneedle array for use as a TCI device, and reported that TCI with the dissolving microneedle array induced an immune response against model antigens. In the present study, we investigated the vaccination efficacy against tetanus and diphtheria, malaria, and influenza using this vaccination system. Our TCI system induced substantial increases in toxoid-specific IgG levels and toxin-neutralizing antibody titer and induced the production of anti-SE36 IgG, which could bind to malaria parasite. On influenza HA vaccination, robust antibody production was elicited in mice that provided complete protection against a subsequent influenza virus challenge. These findings demonstrate that TCI using a dissolving microneedle array can elicit large immune responses against infectious diseases. Based on these results, we are now preparing translational research for human clinical trials.

Coated microneedle arrays for transcutaneous delivery of live virus vaccines

Vaccines are sensitive biologics that require continuous refrigerated storage to maintain their viability. The vast majority of vaccines are also administered using needles and syringes. The need for cold chain storage and the significant logistics surrounding needle-and-syringe vaccination is constraining the success of immunization programs. Recombinant live viral vectors are a promising platform for the development of vaccines against a number of infectious diseases, however these viruses must retain infectivity to be effective. Microneedles offer an effective and painless method for delivery of vaccines directly into skin that in the future could provide solutions to current vaccination issues. Here we investigated methods of coating live recombinant adenovirus and modified vaccinia virus Ankara (MVA) vectors onto solid microneedle arrays. An effective spray-coating method, using conventional pharmaceutical processes, was developed, in tandem with suitable sugar-based formulations, which produces arrays with a unique coating of viable virus in a dry form around the shaft of each microneedle on the array. Administration of live virus-coated microneedle arrays successfully resulted in virus delivery, transcutaneous infection and induced an antibody or CD8(+) T cell response in mice that was comparable to that obtained by needle-and-syringe intradermal immunization. To our knowledge, this is the first report of successful vaccination with recombinant live viral vectored vaccines coated on microneedle delivery devices.

A global health partnership's use of time-limited support to catalyze health practice change: the case of GAVI's Injection Safety Support

This paper presents the findings of a study to assess the effectiveness and sustainability of a GAVI (Global Alliance of Vaccines and Immunization) sponsored, time-limited Injection Safety (INS) support. The support came in two forms: 1) in-kind, in the form of AD syringes and safety boxes, and 2) in cash, for those countries that already had a secure, multi-year source of AD syringes and safety boxes, but proposed to use INS support to strengthen their injection safety activities. In total, GAVI gave INS support for a three-year period to 58 countries: 46 with commodities and 12 with cash support. To identify variables that might be associated with financial sustainability, frequencies and cross-tabulations were run against various programmatic and socio-economic variables in the 58 countries. All but two of the 46 commodity-recipient countries were able to replace and sustain the use of AD syringes and safety boxes after the end of their GAVI INS support despite the fact that standard disposable syringes are less costly than ADs (10–15 percent differential). In addition, all 12 cash-recipient countries continued to use AD syringes and safety boxes in their immunization programs in the years following GAVI INS assistance. At the same time, countries were often not prepared for the increased waste management requirements associated with the use of the syringes, suggesting the importance of anticipating challenges with the introduction of new technologies. The sustained use of AD syringes in countries receiving injection safety support from GAVI, in a majority of cases through government financing, following the completion of three years of time-limited support, represents an early indication of how GHPs can contribute to improved health outcomes in immunization safety in the world's poorest countries in a sustainable way.

Transcutaneous immunization studies in mice using diphtheria toxoid-loaded vesicle formulations and a microneedle array

Purpose

To determine the immunogenicity of diphtheria toxoid (DT) formulated in two types of vesicles following transcutaneous immunization (TCI) of mice onto microneedle array-treated skin.

Methods

DT-containing cationic liposomes or anionic surfactant-based vesicles were prepared by extrusion and sonication. The physicochemical properties were characterized in terms of size, ζ-potential, vesicle elasticity and antigen association. TCI was performed by applying formulations onto intact or microneedle array-pretreated mice skin, using cholera toxin as an adjuvant. Subcutaneous and intradermal immunizations were as control. Immune responses were evaluated by IgG and neutralizing antibody titers, and the immune-stimulatory properties were assessed using cultured dendritic cells.

Results

Stable DT-containing cationic liposomes (∼150 nm) and anionic vesicles (∼100 nm) were obtained. Incorporation of Span 80 increased liposome elasticity. About 90% and 77% DT was associated with liposomes and vesicles, respectively. TCI of all formulations resulted in substantial antibody titers only if microneedle pretreatment was applied. Co-administration of cholera toxin further augmented the immune responses of TCI. However, vesicle formulations didn’t enhance the immunogenicity on either intact or microneedle-treated skin and showed low stimulatory activity on dendritic cells.

Conclusions

Microneedle pretreatment and cholera toxin, but not antigen association to vesicles, enhances the immunogenicity of topically applied DT.

Immune modulation by adjuvants combined with diphtheria toxoid administered topically in BALB/c mice after microneedle array pretreatment

Purpose

In this study, modulation of the immune response against diphtheria toxoid (DT) by various adjuvants in transcutaneous immunization (TCI) with microneedle array pretreatment was investigated.

Methods

TCI was performed on BALB/c mice with or without microneedle array pretreatment using DT as a model antigen co-administrated with lipopolysaccharide (LPS), Quil A, CpG oligo deoxynucleotide (CpG) or cholera toxin (CT) as adjuvant. The immunogenicity was evaluated by measuring serum IgG subtype titers and neutralizing antibody titers.

Results

TCI with microneedle array pretreatment resulted in a 1,000-fold increase of DT-specific serum IgG levels as compared to TCI. The immune response was further improved by co-administration of adjuvants, showing a progressive increase in serum IgG titers when adjuvanted with LPS, Quil A, CpG and CT. IgG titers of the CT-adjuvanted group reached levels comparable to those obtained after DT-alum subcutaneous injection. The IgG1/IgG2a ratio of DT-specific antibodies decreased in the following sequence: plain DT, Quil A, CT and CpG, suggesting that the immune response was skewed towards the Th1 direction.

Conclusions

The potency and the quality of the immune response against DT administered by microneedle array mediated TCI can be modulated by co-administration of adjuvants.

Reuse prevention syringes for reconstitution of lyophilized vaccines: Operational study and UNICEF plans for expanding introduction

Since the 1990s, the United Nation's Children's Fund has encouraged injection safety for immunizations through bundling vaccines with appropriate amounts of supporting equipment and by supplying autodisable (AD) syringes for injections. However, poor vaccine reconstitution practices continue to be reported worldwide. By 2009, UNICEF will begin to phase out the distribution of standard disposable syringes for vaccine reconstitution and replace them with reuse prevention (RUP) syringes, with a full transition expected by the end of 2010. A field evaluation in Indonesia was conducted to identify introduction requirements, issues with healthcare worker training and acceptance, and RUP syringe performance and safety. Managers and health workers felt that RUP syringes improved injection safety and fit easily into country logistical systems. Healthcare workers felt they were intuitive to use, but recommended special training. The integration of RUP reconstitution syringes by UNICEF could increase injection safety by preventing the reuse of syringes and reducing vaccine contamination.

Rejection of large HPV-16 expressing tumors in aged mice by a single immunization of VacciMax encapsulated CTL/T helper peptides

The incidence of cancer increases significantly in later life, yet few pre-clinical studies of cancer immunotherapy use mice of advanced age. A novel vaccine delivery platform (VacciMax,VM) is described that encapsulates antigens and adjuvants in multilamellar liposomes in a water-in-oil emulsion. The therapeutic potential of VM-based vaccines administered as a single dose was tested in HLA-A2 transgenic mice of advanced age (48-58 weeks old) bearing large palpable TC1/A2 tumors. The VM-based vaccines contained one or more peptides having human CTL epitopes derived from HPV 16 E6 and E7. VM formulations contained a single peptide, a mixture of four peptides or the same four peptides linked together in a single long peptide. All VM formulations contained PADRE and CpG as adjuvants and ISA51 as the hydrophobic component of the water-in-oil emulsion. VM-formulated vaccines containing the four peptides as a mixture or linked together in one long peptide eradicated 19-day old established tumors within 21 days of immunization. Peptide-specific cytotoxic cellular responses were confirmed by ELISPOT and intracellular staining for IFN-gamma producing CD8+ T cells. Mice rendered tumor-free by vaccination were re-challenged in the opposite flank with 10 million HLF-16 tumor cells, another HLA-A2/E6/E7 expressing tumor cell line. None of these mice developed tumors following the re-challenge. In summary, this report describes a VM-formulated therapeutic vaccine with the following unprecedented outcome: a) eradication of large tumors (> 700 mm3) b) in mice of advanced age c) in less than three weeks post-immunization d) following a single vaccination.

Gene gun immunization with clinically relevant allergens aggravates allergen induced pathology and is contraindicated for allergen immunotherapy

Gene gun immunization has been associated with the induction of a heterologous type of immune response characterized by a T(H)1-like immune reaction on the cellular level, i.e. generation of IFN-gamma secreting CD8(+) T-cells, yet a T(H)2 biased serology as indicated by high IgG1:IgG2a ratios and induction of IgE. Nevertheless, gene gun immunization using the model molecule beta-galactosidase has been argued to prevent IgE induction and to promote T(H)1 cells with respect to allergy DNA immunization. In our current study, we evaluated the potential of gene gun immunization to prevent type I allergic reactions comparing beta-galactosidase with two clinically relevant allergens, and further investigated the effect of gene gun immunization on relevant lung parameters. BALB/c mice were immunized with plasmids encoding the birch pollen allergen Bet v 1, the grass pollen allergen Phl p 5, or the model molecule beta-galactosidase, either by gene gun or intradermal injection followed by sensitization and intranasal provocation with the respective allergen. IgG1 and IgG2a antibody titers were determined by ELISA. IgE levels were evaluated in a rat basophil release assay. The severity of eosinophilia was determined in bronchoalveolar lavages, and the overall infiltrate was analyzed by histology on lung paraffin sections. Gene gun immunization induced a T(H)2-biased immune reaction, which did not prevent from production of IgE after subsequent sensitization. This T(H)2 effect was influenced by the nature of the antigen, with a more pronounced T(H)2-bias for the allergens Bet v 1 and Phl p 5 compared to beta-galactosidase. Gene gun immunization with all three antigens promoted eosinophil influx into the lung and did not alleviate lung pathology after intranasal provocation. In contrast to needle injection of plasmid DNA, which triggers a clearly T(H)1-biased and allergy-preventing immune response, gene gun application fails to induce anti-allergic reactions with all tested antigens and is therefore contraindicated for allergen-specific immunotherapy.

Immunization without needles

Most current immunization procedures make use of needles and syringes for vaccine administration. With the increase in the number of immunizations that children around the world routinely receive, health organizations are beginning to look for safer alternatives that reduce the risk of cross-contamination that arises from needle reuse. This article focuses on contemporary developments in needle-free methods of immunization, such as liquid-jet injectors, topical application to the skin, oral pills and nasal sprays.

Behavioral responses to two intranasal vaccine applicators in horses and ponies

OBJECTIVE

To evaluate behavioral compliance of horses and ponies with simulated intranasal vaccination and assess development of generalized aversion to veterinary manipulations.

DESIGN

Clinical trial.

ANIMALS

28 light horse mares, 3 pony geldings, 2 light horse stallions, and 3 pony stallions that had a history of compliance with veterinary procedures.

PROCEDURE

Behavioral compliance with 2 intranasal vaccine applicators was assessed. Compliance with standard physical examination procedures was assessed before and after a single experience with either of the applicators or a control manipulation to evaluate development of generalized aversion to veterinary manipulation.

RESULTS

In all 30 horses, simulated intranasal vaccination or the control manipulation could be performed without problematic avoidance behavior, and simulated intranasal vaccination did not have any significant effect on duration of or compliance with a standardized physical examination that included manipulation of the ears, nose, and mouth. Results were similar for the 2 intranasal vaccine applicators, and no difference in compliance was seen between horses in which warm versus cold applicators were used. For 3 of the 6 ponies, substantial avoidance behavior was observed in association with simulated intranasal vaccination, and compliance with physical examination procedures decreased after simulated intranasal vaccination.

CONCLUSIONS AND CLINICAL RELEVANCE

Although some compliance problems were seen with ponies, neither problems with compliance with simulated intranasal vaccination nor adverse effects on subsequent physical examination were identified in any of the horses. Further study is needed to understand factors involved in practitioner reports of aversion developing in association with intranasal vaccination.

A systematic review to ascertain whether the standard needle is more effective than a longer or wider needle in reducing the incidence of local reaction in children receiving primary immunization

CONTEXT

Millions of doses of vaccines are given to children within the United Kingdom (UK) each year, yet there is conflicting national guidance on the length of needle to use. Prefilled syringes come supplied with 25 Gauge 16 millimetres long needles.

OBJECTIVES

A systematic review was completed to answer the clinical question of whether the standard needle is more effective than a longer and/or wider needle in reducing local reactions in children receiving primary immunizations.

METHODS

DATA SOURCES

A comprehensive search strategy, including searching of electronic databases, hand searching, reference/citation searching, contacting researchers in the field and searching for unpublished literature.

STUDY SELECTION

Selection of studies was guided by the clinical question, the inclusion and exclusion criteria being applied by two people independently. Study quality assessment: An established quality checklist was used. Critical analysis of the quality of the components of the studies is included in the discussion.

DATA EXTRACTION

Two people independently applied a data extraction form, designed for the study.

RESULTS

(1). Rev Man (a Windows-based software package used by the Cochrane Collaboration) was used to perform a meta-analysis on the binary results of two small studies using Relative Risk as the summary statistic 16 mm vs. 25 mm needle. (2). The pooled Relative Risk for redness was 2.52 [95% confidence interval (CI) fixed 1.70-3.72] P < 0.00001. (3). The pooled Relative Risk for swelling was 2.31 (95% CI fixed 1.55-3.43) P < 0.00003.

CONCLUSION

(1). The results are statistically very highly significant and favour the use of the 25 millimetre long needle. (2). No studies were identified to separate the effect of the gauge of the needle used, but the discussion shows that needle length is the most important variable. (3). The results should be incorporated into any future guidelines on vaccine administration in the UK.

DNA immunization via intramuscular and intradermal routes using a gene gun provides different magnitudes and durations on immune response

We investigated the antibody (Ab) and cytotoxic T lymphocyte (CTL) responses to gene gun (GG)-mediated DNA immunization via the intramuscular (i.m.) and intradermal (i.d.) routes. BALB/c mice were immunized five times at weekly intervals with plasmid DNA encoding enhanced green fluorescent protein (EGFP). EGFP production was rapidly detected in the target tissues after injection via either delivery route. There were significant differences in the magnitude and duration of the Ab and CTL responses according to the route employed. Intradermal injection elicited higher Ab and CTL responses to EGFP than i.m. injection 1 week after the last immunization. However, both immune responses were reduced rapidly 5 weeks after the last immunization via i.d. injection. In contrast, in mice injected via the i.m. routes, Ab and CTL responses 5 weeks after the last immunization remained at levels similar to those detected after 1 week. All mice generated a predominantly IgG1 Ab response via either route. These findings suggest that a combination of these two routes of DNA immunization would provide optimal conditions for induction of a broad immune response, and this information is expected to be very important for future applications of DNA vaccination.

Introducing auto-disable syringes to the national immunization programme in Madagascar

OBJECTIVE

To evaluate the safety and coverage benefits of auto-disable (AD) syringes, weighed against the financial and logis- tical costs, and to create appropriate health policies in Madagascar.

METHODS

Fifteen clinics in Madagascar, trained to use AD syringes, were randomized to implement an AD syringe only, mixed (AD syringes used only on non-routine immunization days), or sterilizable syringe only (control) programme. During a five-week period, data on administered vaccinations were collected, interviews were conducted, and observations were recorded.

FINDINGS

The use of AD syringes improved coverage rates by significantly increasing the percentage of vaccines administered on non-routine immunization days (AD-only 4.3%, mixed 5.7%, control 1.1% (P<0.05)). AD-only clinics eliminated sterilization sessions for vaccinations, whereas mixed clinics reduced the number of sterilization sessions by 64%. AD syringes were five times more expensive than sterilizable syringes, which increased AD-only and mixed clinics' projected annual injection costs by 365% and 22%, respectively. However, introducing AD syringes for all vaccinations would only increase the national immunization budget by 2%.

CONCLUSION

The use of AD syringes improved vaccination coverage rates by providing ready-to-use sterile syringes on non-routine immunization days and decreasing the number of sterilization sessions, thereby improving injection safety. The mixed programme was the most beneficial approach to phasing in AD syringes and diminishing logistical complications, and it had minimal costs. AD syringes, although more expensive, can feasibly be introduced into a developing country's immunization programme to improve vaccination safety and coverage.

Immunisation safety: a priority of the World Health Organization's Department of Vaccines and Biologicals

In 1999, the World Health Organization (WHO) Department of Vaccines and Biologicals launched the Immunisation Safety Priority Project to boost its activities in this area, with the aim of establishing a comprehensive system to ensure the safety of all immunisations given in national immunisation programmes. Countries are the primary focus of this project. The WHO has a role to play not only because of its technical and normative role but also because of its privileged relationship with country authorities and other partners, its global vision and mandate, and because it is perceived as free from conflicts of interest. There are four areas of focus in the project: quality control and assessment tools to ensure vaccine safety from clinical trials up to and including the point of use;research and development of safer and simpler delivery systems; access to safer and more efficient systems for vaccine delivery and sharps waste management; and mechanisms to respond promptly and effectively to vaccine safety concerns. The project emphasises the importance of advocating safety and developing necessary infrastructure and human resource to properly deal with immunisation related safety issues at a national level.

Effect of needle length on incidence of local reactions to routine immunisation in infants aged 4 months: randomised controlled trial

OBJECTIVE

To compare rates of local reactions associated with two needle sizes used to administer routine immunisations to infants.

DESIGN

Randomised controlled trial.

SETTING

Routine immunisation clinics in eight general practices in Buckinghamshire.

PARTICIPANTS

Healthy infants attending for third primary immunisation due at 16 weeks of age: 119 infants were recruited, and 110 diary cards were analysed.

INTERVENTIONS

Immunisation with 25 gauge, 16 mm, orange hub needle or 23 gauge, 25 mm, blue hub needle.

MAIN OUTCOME MEASURES

Parental recordings of redness, swelling, and tenderness for three days after immunisation.

RESULTS

Rate of redness with the longer needle was initially two thirds the rate with the smaller needle (relative risk 0.66 (95% confidence interval 0.45 to 0.99), P=0.04), and by the third day this had decreased to a seventh (relative risk 0.13 (0.03 to 0.56), P=0.0006). Rate of swelling with the longer needle was initially about a third that with the smaller needle (relative risk 0.39 (0.23 to 0.67), P=0.0002), and this difference remained for all three days. Rates of tenderness were also lower with the longer needle throughout follow up, but not significantly (relative risk 0.60 (0.29 to 1.25), P=0.17).

CONCLUSIONS

Use of 25 mm needles significantly reduced rates of local reaction to routine infant immunisation. On average, for every five infants vaccinated, use of the longer needle instead of the shorter needle would prevent one infant from experiencing any local reaction. Vaccine manufacturers should review their policy of supplying the shorter needle in vaccine packs.

At-birth immunisation against hepatitis B using a novel pre-filled immunisation device stored outside the cold chain

We evaluated the immunogenicity of hepatitis B (HB) vaccine in UniJect, a pre-filled, non-reusable injection device, stored at tropical temperatures for up to one month and used to give the first dose of HB vaccine to newborns. Infants in Tabanan district, Bali, Indonesia, were given their first dose of HB vaccine with UniJect stored out of the cold chain, UniJect stored in the cold chain; or standard syringe, needle and multidose vial stored in the cold chain. Subsequent doses were given by usual means and blood samples drawn 4-6 weeks after the third dose. No significant differences were found in seroconversion rates or geometric mean titres of HB surface antibody between the three groups.

Use of SoloShot autodestruct syringes compared with disposable syringes, in a national immunization campaign in Indonesia

Autodestruct syringes can reduce the improper reuse of syringes, which present a significant risk in the transmission of bloodborne pathogens in developing countries, especially during immunization campaigns owing to the high number of injections given per session. SoloShot is an autodestruct syringe, distributed by UNICEF, which has been shown to be safer and easier to use than standard syringes. This study analyses the accuracy and dose-efficiency of SoloShot, compared with disposable syringes, during a national tetanus toxoid immunization campaign on the Indonesian island of Lombok. Observation and dose measurements revealed that SoloShot syringes delivered more precise and consistent doses and 15% more doses per vial than disposable syringes. Vaccine savings may partially be offset by the higher price of SoloShot. Vaccinators preferred SoloShot, describing it as easier to use, faster, and more accurate than the disposable syringe. The study indicates that SoloShot is highly appropriate for use in immunization campaigns by reducing vaccine wastage and improving injection safety.

Auto-disable syringes for immunization: issues in technology transfer

WHO and its partners recommend the use of auto-disable syringes, "bundled" with the supply of vaccines when donor dollars are used, in all mass immunization campaigns, and also strongly advocate their use in routine immunization programmes. Because of the relatively high price of auto-disable syringes, WHO's Technical Network for Logistics in Health recommends that activities be initiated to encourage the transfer of production technology for these syringes as a means of promoting their use and enhancing access to the technology. The present article examines factors influencing technology transfer, including feasibility, corporate interest, cost, quality assurance, intellectual property considerations, and probable time frames for implementation. Technology transfer activities are likely to be complex and difficult, and may not result in lower prices for syringes. Guidelines are offered on technology transfer initiatives for auto-disable syringes to ensure the quality of the product, the reliability of the supply, and the feasibility of the technology transfer activity itself.

Particle-mediated nucleic acid immunization

Nucleic acid immunization involves the direct in vivo administration of antigen-encoding plasmid DNA molecules that results in the de novo production of correctly folded microbial antigens at the site of DNA delivery. While this process can lead to the development of neutralizing antibody responses recognizing authentic protein conformations, in vivo antigen production also results in epitope presentation via the MHC class I antigen processing pathway, leading to the elicitation of cytotoxic cellular immune responses. Recent efforts in the authors' laboratories have focused on use of the Accell gene delivery system (gene gun) to achieve the direct, intracellular delivery of small quantities of DNA into cells of the epidermis. The gene gun approach to nucleic acid vaccination capitalizes on the synergistic combination of an effective DNA delivery system and a target tissue that serves as a major immunological inductive site. Experimental gene gun-based nucleic acid vaccines can achieve potent humoral and cytotoxic cellular immune responses in rodent models following immunization with as little as 16 ng of DNA. Equally strong responses have also been elicited in larger animals, such as pigs and monkeys, following epidermal immunization with as little as 2 to 4 micrograms of DNA.

Reducing the risk of unsafe injections in immunization programmes: financial and operational implications of various injection technologies

The unsafe use and disposal of injection equipment continues to put patients, health care workers, and the general community at risk of infections such as hepatitis B virus and human immunodeficiency virus. Although the potential for unsafe injection practices varies substantially with the type of equipment that is used, technology alone cannot totally eliminate the risk. A knowledge of the cost, practicality and, most importantly, the potential for misuse, is critical for selecting the most appropriate injection equipment for each immunization setting. Four types of injection equipment are currently available for administering vaccines: sterilizable needles and syringes; standard disposable needles and syringes; autodestruct needles and syringes; and jet injectors. In general, the cost per injection is lowest with sterilizable equipment and highest with autodestruct. However, only autodestruct syringes virtually eliminate the risk of unsafe injection practices. Owing to differences in cost and programme factors, in some settings it may be appropriate to use a combination of equipment. For example, autodestruct syringes may be used in areas where it is difficult to ensure adequate supervision, while in medium-sized, fixed-site clinics with safe injection practices, sterilizable equipment will be the most cost-effective.

Safety, effectiveness and ease of use of a non-reusable syringe in a developing country immunization programme

Unsterile needles and syringes may transmit blood-borne infectious agents such as HIV and hepatitis B virus. The emergence of these diseases as major public health concerns and the risk of nosocomial transmission has heightened interest in the development of single-use injection devices. WHO and UNICEF embarked on a programme to develop and introduce these devices in 1987. We report on a field trial in Karachi, Pakistan, of the SoloShot (SS) plastic disposable syringe, which has a metal clip in the syringe barrel to prevent second-time withdrawal of the plunger. A conventional disposable syringe (CS) was used as a comparison. We observed 48 vaccinators giving 2400 injections with the SS and 1440 with the CS; 98.7% of SS performed as designed. The average volume required per delivered dose was comparable for the two syringes and was delivered more quickly with SS. Training and experience had a small but statistically significant effect on several aspects of SS use. Vaccinators who indicated a syringe preference preferred SS on 7 out of 9 indicators. SS is safe and effective in preventing reuse and is easier and quicker to use than the CS. Vaccinators require little, if any, special training. It could directly replace disposable syringes in expanded programmes on immunization (EPI) in countries where use of unsterile disposable devices occurs or when sterilization is not practical.

Mass immunization technique

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