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CURATOR

I am a scientist specialized in mitochondria and genetics, but above all, I am just curious guy who loves learning new things.

PINBOARD SUMMARY

Vaccinations are essential for public health… but they can be itchy business

In 10 seconds? Aluminium, a common adjuvant in vaccines, is necessary to stimulate and strengthen the immunological power of vaccination, but may cause unwanted side effects, like long-lasting itching and allergies in children.

What are adjuvants and why are they necessary? An adjuvant is an added ingredient in vaccines that helps to create a stronger immune response in the patient’s body, ensuring that patients will be protected against the germ targeted by the vaccine. Aluminium salts, such as aluminium hydroxide, have been commonly used as adjuvants for the past 70 years, and are present today in Infanrix® and Pentavac®, the two most commonly used DTP (Diphtheria, Tetanus, and Pertussis) vaccines in Europe.

If they have been used for over 70 years they must be safe, right? Similarly to medications, vaccines and their components may cause secondary effects, and recent studies seem to agree that although these effects are rare, they are significant. The most common side effects from aluminium adjuvants are itching granulomas and aluminium contact allergies, but more severe outcomes, such as autoimmune reactions and negative consequences on the central nervous system, have been reported, although these results are highly controversial.

If the most probable side effect is only an itch, then there is no need to worry. Well, did I mention that this itch lasts over 5 years? So, yes, these effects are mostly benign but definitely not the most enjoyable feeling a toddler could experience, without mentioning contact allergies to aluminium. But the biggest problem is that almost half of the families will refuse booster vaccinations if their child suffered from these side effects, leaving the child unprotected from infection.

Are there any alternatives? There are some possibilities under study, like dissolving microneedle patches, which provide improved immunogenicity and could eventually eliminate the need for conventional adjuvants by taking advantage of the rich network of immunologic antigen-presenting cells in the skin; or molecular adjuvants, like cytokines or inhibitors of immune suppressive pathways, with lower negative consequences.

20 ITEMS PINNED

The safety, immunogenicity, and acceptability of inactivated influenza vaccine delivered by microneedle patch (TIV-MNP 2015): a randomised, partly blinded, placebo-controlled, phase 1 trial.

Abstract: Microneedle patches provide an alternative to conventional needle-and-syringe immunisation, and potentially offer improved immunogenicity, simplicity, cost-effectiveness, acceptability, and safety. We describe safety, immunogenicity, and acceptability of the first-in-man study on single, dissolvable microneedle patch vaccination against influenza.The TIV-MNP 2015 study was a randomised, partly blinded, placebo-controlled, phase 1, clinical trial at Emory University that enrolled non-pregnant, immunocompetent adults from Atlanta, GA, USA, who were aged 18-49 years, naive to the 2014-15 influenza vaccine, and did not have any significant dermatological disorders. Participants were randomly assigned (1:1:1:1) to four groups and received a single dose of inactivated influenza vaccine (fluvirin: 18 μg of haemagglutinin per H1N1 vaccine strain, 17 μg of haemagglutinin per H3N2 vaccine strain, and 15 μg of haemagglutinin per B vaccine strain) (1) by microneedle patch or (2) by intramuscular injection, or received (3) placebo by microneedle patch, all administered by an unmasked health-care worker; or received a single dose of (4) inactivated influenza vaccine by microneedle patch self-administered by study participants. A research pharmacist prepared the randomisation code using a computer-generated randomisation schedule with a block size of 4. Because of the nature of the study, participants were not masked to the type of vaccination method (ie, microneedle patch vs intramuscular injection). Primary safety outcome measures are the incidence of study product-related serious adverse events within 180 days, grade 3 solicited or unsolicited adverse events within 28 days, and solicited injection site and systemic reactogenicity on the day of study product administration through 7 days after administration, and secondary safety outcomes are new-onset chronic illnesses within 180 days and unsolicited adverse events within 28 days, all analysed by intention to treat. Secondary immunogenicity outcomes are antibody titres at day 28 and percentages of seroconversion and seroprotection, all determined by haemagglutination inhibition antibody assay. The trial is completed and registered with ClinicalTrials.gov, number NCT02438423.Between June 23, 2015, and Sept 25, 2015, 100 participants were enrolled and randomly assigned to a group. There were no treatment-related serious adverse events, no treatment-related unsolicited grade 3 or higher adverse events, and no new-onset chronic illnesses. Among vaccinated groups (vaccine via health-care worker administered microneedle patch or intramuscular injection, or self-administered microneedle patch), overall incidence of solicited adverse events (n=89 vs n=73 vs n=73) and unsolicited adverse events (n=18 vs n=12 vs n=14) were similar. Reactogenicity was mild, transient, and most commonly reported as tenderness (15 [60%] of 25 participants [95% CI 39-79]) and pain (11 [44%] of 25 [24-65]) after intramuscular injection; and as tenderness (33 [66%] of 50 [51-79]), erythema (20 [40%] of 50 [26-55]), and pruritus (41 [82%] of 50 [69-91]) after vaccination by microneedle patch application. The geometric mean titres were similar at day 28 between the microneedle patch administered by a health-care worker versus the intramuscular route for the H1N1 strain (1197 [95% CI 855-1675] vs 997 [703-1415]; p=0·5), the H3N2 strain (287 [192-430] vs 223 [160-312]; p=0·4), and the B strain (126 [86-184] vs 94 [73-122]; p=0·06). Similar geometric mean titres were reported in participants who self-administered the microneedle patch (all p>0·05). The seroconversion percentages were significantly higher at day 28 after microneedle patch vaccination compared with placebo (all p<0·0001) and were similar to intramuscular injection (all p>0·01).Use of dissolvable microneedle patches for influenza vaccination was well tolerated and generated robust antibody responses.National Institutes of Health.

Pub.: 02 Jul '17, Pinned: 12 Sep '17

Microneedle patch delivery of influenza vaccine during pregnancy enhances maternal immune responses promoting survival and long-lasting passive immunity to offspring.

Abstract: Influenza virus causes life-threatening infections in pregnant women and their newborns. Immunization during pregnancy is the most effective means of preventing maternal and infant mortality/morbidity; however, influenza vaccination rates of pregnant women remain under 50%. Furthermore, the availability of vaccines in low-resource populations is limited. Skin immunization with microneedle patches (MN) is a novel and safe vaccination platform featuring thermostable vaccine formulations. Cold-chain independence and the potential for self-administration can expand influenza vaccination coverage in developing countries. In this study of pregnant BALB/c mice immunized with subunit H1N1 influenza vaccine, we demonstrate the advantage of skin vaccination over intramuscular delivery of a two-fold higher vaccine dose. MN vaccine induced superior humoral immune responses and conferred protective immunity against a lethal challenge dose of homologous influenza virus. Importantly, MN vaccination of mice at mid-gestation resulted in enhanced and long-lasting passive immunity of the offspring, measured by neutralizing antibody titers and survival rates after virus challenge. We conclude that skin vaccination using MN is a superior immunization approach with the potential to overcome immune tolerance observed in pregnancy, and lower vaccination costs through antigen dose-sparing, which is especially relevant in underserved countries.

Pub.: 20 Jul '17, Pinned: 12 Sep '17

Cumulative and episodic vaccine aluminum exposure in a population-based cohort of young children.

Abstract: In addition to antigens, vaccines contain small amounts of preservatives, adjuvants, and residual substances from the manufacturing process. Some parents have concerns about the safety of these ingredients, yet no large epidemiological studies have specifically examined associations between health outcomes and vaccine ingredients, other than thimerosal. This study examined the extent to which the Vaccine Safety Datalink (VSD) could be used to study vaccine ingredient safety in children.Children born 2004-2011 were identified in VSD data. Using immunization records, two cohorts were identified: children who were up-to-date and children who were undervaccinated before age 2 years. A database was also created linking vaccine type and manufacturer with ingredient amounts documented in vaccine package inserts. Thirty-four ingredients in two or more infant vaccines were identified. However, only amounts (in mg) for aluminum were consistently documented and commonly contained in infant vaccines. Analyses compared vaccine aluminum exposure across cohorts and determined the statistical power for studying associations between aluminum exposure and hypothetical vaccine adverse events.Among 408,608 children, mean cumulative vaccine aluminum exposure increased from 1.11 to 4.00 mg between ages 92-730 days. Up-to-date children were exposed to 11-26% more aluminum from vaccines than undervaccinated children. Power analyses demonstrated that safety studies of aluminum could detect relative risks ranging from 1.1 to 5.8 for a range of adverse event incidence.The safety of vaccine aluminum exposure can be feasibly studied in the VSD. However, possible biological mechanisms and confounding variables would need to be considered before conducting any studies.

Pub.: 01 Nov '15, Pinned: 12 Sep '17

Improved immunogenicity of individual influenza vaccine components delivered with a novel dissolving microneedle patch stable at room temperature.

Abstract: Prevention of seasonal influenza epidemics and pandemics relies on widespread vaccination coverage to induce protective immunity. In addition to a good antigenic match with the circulating viruses, the effectiveness of individual strains represented in the trivalent vaccines depends on their immunogenicity. In this study, we evaluated the immunogenicity of H1N1, H3N2, and B seasonal influenza virus vaccine strains delivered individually with a novel dissolving microneedle patch and the stability of this formulation during storage at 25 °C. Our data demonstrate that all strains retained their antigenic activity after incorporation in the dissolving patches as measured by single radial diffusion (SRID) assay and immune responses to vaccination in BALB/c mice. After a single immunization, all three antigens delivered with microneedle patches induced superior neutralizing antibody titers compared to intramuscular immunization. Cutaneous antigen delivery was especially beneficial for the less immunogenic B strain. Mice immunized with dissolving microneedle patches encapsulating influenza A/Brisbane/59/07 (H1N1) vaccine were fully protected against lethal challenge by homologous mouse-adapted influenza virus. All vaccine components retained activity during storage at room temperature for at least 3 months as measured in vitro by SRID assay and in vivo by mouse immunization studies. Our data demonstrate that dissolving microneedle patches are a promising advance for influenza cutaneous vaccination due to improved immune responses using less immunogenic influenza antigens and enhanced stability.

Pub.: 22 Apr '15, Pinned: 12 Sep '17

Inflammatory responses following intramuscular and subcutaneous immunization with aluminum-adjuvanted or non-adjuvanted vaccines.

Abstract: Aluminum-adjuvanted vaccines are administered through an intramuscular injection (IM) in the US and EU, however, a subcutaneous injection (SC) has been recommended in Japan because of serious muscle contracture previously reported following multiple IMs of antibiotics. Newly introduced adjuvanted vaccines, such as the human papillomavirus (HPV) vaccines, have been recommended through IM. In the present study, currently available vaccines were evaluated through IM in mice. Aluminum-adjuvanted vaccines induced inflammatory nodules at the injection site, which expanded into the intra-muscular space without any muscle degeneration or necrosis, whereas non-adjuvanted vaccines did not. These nodules consisted of polymorph nuclear neutrophils with some eosinophils within the initial 48h, then monocytes/macrophages 1 month later. Inflammatory nodules were observed 6 months after IM, had decreased in size, and were absorbed 12 months after IM, which was earlier than that after SC. Cytokine production was examined in the injected muscular tissues and AS04 adjuvanted HPV induced higher IL-1β, IL-6, KC, MIP-1, and G-CSF levels in muscle tissues than any other vaccine, but similar serum cytokine profiles were observed to those induced by the other vaccines. Currently available vaccines did not induce muscular degeneration or fibrotic scar as observed with muscle contracture caused by multiple IMs of antibiotics in the past.

Pub.: 29 Apr '14, Pinned: 12 Sep '17

Aluminium based adjuvants and their effects on mitochondria and lysosomes of phagocytosing cells.

Abstract: Aluminium oxyhydroxide, Al(OH)3 is one of few compounds approved as an adjuvant in human vaccines. However, the mechanism behind its immune stimulating properties is still poorly understood. In vitro co-culture of an aluminium adjuvant and the human monocytic cell line THP-1 resulted in reduced cell proliferation. Inhibition occurred at concentrations of adjuvant several times lower than would be found at the injection site using a vaccine formulation containing an aluminium adjuvant. Based on evaluation of the mitochondrial membrane potential, THP-1 cells showed no mitochondrial rupture after co-culture with the aluminium adjuvant, instead an increase in mitochondrial activity was seen. The THP-1 cells are phagocytosing cells and after co-culture with the aluminium adjuvant the phagosomal pathway was obstructed. Primary or early phagosomes mature into phagolysosomes with an internal pH of 4.5 - 5 and carry a wide variety of hydrolysing enzymes. Co-culture with the aluminium adjuvant yielded a reduced level of acidic vesicles and cathepsin L activity, a proteolytic enzyme of the phagolysosomes, was almost completely inhibited. THP-1 cells are an appropriate in vitro model in order to investigate the mechanism behind the induction of a phagocytosing antigen presenting cell into an inflammatory cell by aluminium adjuvants. Much information will be gained by investigating the phagosomal pathway and what occurs inside the phagosomes and to elucidate the ultimate fate of phagocytosed aluminium particles.

Pub.: 03 Sep '13, Pinned: 12 Sep '17

Sixty-four children with persistent itching nodules and contact allergy to aluminium after vaccination with aluminium-adsorbed vaccines-prognosis and outcome after booster vaccination.

Abstract: Persistent itching subcutaneous nodules and aluminium (Al) allergy have been described after vaccination with Al-adsorbed vaccines but are considered rare. Little is known about the prognosis. Sixty-four children with itching nodules following vaccination with diphtheria-tetanus-pertussis (DTP) vaccines currently used in Sweden (Infanrix® and Pentavac®) were spontaneously reported to the authors from 1999 and followed for up to 12 years. The median duration of itching was 5 years in the 44 children who were free or almost free from symptoms at the latest follow-up. Typical findings were a long interval between vaccination and onset of symptoms (months or years) and intensified itching during intercurrent infections. Contact allergy to aluminium was demonstrated in 60/63 children (95 %). Neither the incidence nor differences between the two vaccines can be estimated from this study, but vaccine-induced itching nodules are probably more common than hitherto realised. The median interval between onset of symptoms and diagnosis was 8 months in a region where nurses were educated to recognise the condition compared to 2 years in other regions. Booster vaccination with DTP-polio was postponed or declined by 15/40 families in fear for new problems. Out of 25 children who received a booster dose, only two had new itching nodules.Intensely itching subcutaneous nodules (vaccination granulomas) and contact allergy to aluminium may occur after primary vaccination with the two most commonly used DTP vaccines in Europe. The condition is probably underreported. Symptoms may last for at least 4-5 years but eventually seem to subside.

Pub.: 12 Oct '12, Pinned: 12 Sep '17