Standardisation of inactivated influenza vaccines-Learning from history.

The single radial immunodiffusion assay has been the accepted method for determining the potency of inactivated influenza vaccines since 1978. The worldwide adoption of this assay for vaccine standardisation was facilitated through collaborative studies that demonstrated a high level of reproducibility and its applicability to the different types of influenza vaccine being produced at that time. Clinical evidence indicated the relevance of SRID as a potency assay. Unique features of the SRID assay are likely responsible for its longevity even as newer technologies for vaccine characterisation have been developed and refined. Nevertheless, there are significant limitations to the SRID assay that indicate the need for improvement, and there has been a substantial amount of work undertaken in recent years to develop and evaluate alternative potency assays, including collaborative studies involving research laboratories, regulatory agencies and vaccine manufacturers. Here, we provide an overview of the history of inactivated influenza vaccine potency testing, the current state of alternative assay development and the some of the major challenges to be overcome before implementation of new assays for potency determination.

Surveillance for Silicosis Deaths Among Persons Aged 15-44 Years - United States, 1999-2015.

Silicosis is usually a disease of long latency affecting mostly older workers; therefore, silicosis deaths in young adults (aged 15-44 years) suggests acute or accelerated disease.* To understand the circumstances surrounding silicosis deaths among young persons, CDC analyzed the underlying and contributing causes† of death using multiple cause-of-death data (1999-2015) and industry and occupation information abstracted from death certificates (1999-2013). During 1999-2015, among 55 pneumoconiosis deaths of young adults with International Classification of Diseases, Tenth Revision (ICD-10) code J62 (pneumoconiosis due to dust containing silica),§ 38 (69%) had code J62.8 (pneumoconiosis due to other dust containing silica), and 17 (31%) had code J62.0 (pneumoconiosis due to talc dust) listed on their death certificate. Decedents whose cause of death code was J62.8 most frequently worked in the manufacturing and construction industries and production occupations where silica exposure is known to occur. Among the 17 decedents who had death certificates listing code J62.0 as cause of death, 13 had certificates with an underlying or a contributing cause of death code listed that indicated multiple drug use or drug overdose. In addition, 13 of the 17 death certificates listing code J62.0 as cause of death had information on decedent's industry and occupation; among the 13 decedents, none worked in talc exposure-associated jobs, suggesting that their talc exposure was nonoccupational. Examining detailed information on causes of death (including external causes) and industry and occupation of decedents is essential for identifying silicosis deaths associated with occupational exposures and reducing misclassification of silicosis mortality.

Malignant Mesothelioma Mortality - United States, 1999-2015.

Malignant mesothelioma is a neoplasm associated with occupational and environmental inhalation exposure to asbestos* fibers and other elongate mineral particles (EMPs) (1-3). Patients have a median survival of approximately 1 year from the time of diagnosis (1). The latency period from first causative exposure to malignant mesothelioma development typically ranges from 20 to 40 years but can be as long as 71 years (2,3). Hazardous occupational exposures to asbestos fibers and other EMPs have occurred in a variety of industrial operations, including mining and milling, manufacturing, shipbuilding and repair, and construction (3). Current exposures to commercial asbestos in the United States occur predominantly during maintenance operations and remediation of older buildings containing asbestos (3,4). To update information on malignant mesothelioma mortality (5), CDC analyzed annual multiple cause-of-death records† for 1999-2015, the most recent years for which complete data are available. During 1999-2015, a total of 45,221 deaths with malignant mesothelioma mentioned on the death certificate as the underlying or contributing cause of death were reported in the United States, increasing from 2,479 deaths in 1999 to 2,597 in 2015 (in the same time period the age-adjusted death rates§ decreased from 13.96 per million in 1999 to 10.93 in 2015). Malignant mesothelioma deaths increased for persons aged ≥85 years, both sexes, persons of white, black, and Asian or Pacific Islander race, and all ethnic groups. Despite regulatory actions and the decline in use of asbestos the annual number of malignant mesothelioma deaths remains substantial. The continuing occurrence of malignant mesothelioma deaths underscores the need for maintaining measures to prevent exposure to asbestos fibers and other causative EMPs and for ongoing surveillance to monitor temporal trends.

Notes from the Field: Update: Silicosis Mortality - United States, 1999-2013.

Silicosis is a potentially fatal but preventable occupational lung disease caused by inhaling respirable crystalline silica (silica). Chronic silicosis, the most common form, occurs after exposure to relatively low silica concentrations for >10 years. Accelerated silicosis occurs after 5-10 years of exposure to higher silica levels, and acute silicosis can occur after only weeks or months of exposure to extremely high silica concentrations. New national mortality data for silicosis have become available since a previous report on silicosis surveillance was published earlier this year. CDC reviewed multiple cause-of-death mortality files from the National Center for Health Statistics to analyze deaths from silicosis (International Classification of Diseases, 10th Revision diagnosis code J62: a pneumoconiosis due to dust containing silica) reported during 1999-2013. Each record lists one underlying cause of death (the disease or injury that initiated the chain of events that led directly and inevitably to death), and up to 20 contributing causes of death (other significant conditions contributing to death but not resulting in underlying cause). Available death certificates from 35 states were reviewed for the period 2004-2006 to identify occupations associated with silicosis among decedents aged 15-44 years. Results indicate that despite substantial progress in eliminating silicosis, silicosis deaths continue to occur. Of particular concern are silicosis deaths in young adults (aged 15-44 years). These young deaths likely reflect higher exposures than those causing chronic silicosis mortality in older persons, some of sufficient magnitude to cause severe disease and death after relatively short periods of exposure. A total of 12 such deaths occurred during 2011-2013, with nine that had silicosis listed as the underlying cause of death.

Silicosis mortality trends and new exposures to respirable crystalline silica - United States, 2001-2010.

Silicosis is a preventable occupational lung disease caused by the inhalation of respirable crystalline silica dust and can progress to respiratory failure and death. No effective specific treatment for silicosis is available; patients are provided supportive care, and some patients may be considered for lung transplantation. Chronic silicosis can develop or progress even after occupational exposure has ceased. The number of deaths from silicosis declined from 1,065 in 1968 to 165 in 2004. Hazardous occupational exposures to silica dust have long been known to occur in a variety of industrial operations, including mining, quarrying, sandblasting, rock drilling, road construction, pottery making, stone masonry, and tunneling operations. Recently, hazardous silica exposures have been newly documented during hydraulic fracturing of gas and oil wells and during fabrication and installation of engineered stone countertops. To describe temporal trends in silicosis mortality in the United States, CDC analyzed annual multiple cause-of-death data for 2001-2010 for decedents aged ≥15 years. During 2001-2010, a total of 1,437 decedents had silicosis coded as an underlying or contributing cause of death. The annual number of silicosis deaths declined from 164 (death rate† = 0.74 per 1 million population) in 2001 to 101 (0.39 per 1 million) in 2010 (p = 0.002). Because of new operations and tasks placing workers at risk for silicosis, efforts to limit workplace exposure to crystalline silica need to be maintained.

Diseases attributable to asbestos exposure: years of potential life lost, United States, 1999-2010.

BACKGROUND: Although asbestos use has been restricted in recent decades, asbestos-associated deaths continue to occur in the United States. OBJECTIVES: We evaluated premature mortality and loss of potentially productive years of life attributable to asbestos-associated diseases. METHODS: Using 1999-2010 National Center for Health Statistics mortality data, we identified decedents aged ≥25 years whose death certificate listed asbestosis and malignant mesothelioma as the underlying cause of death. We computed years of potential life lost to life expectancy (YPLL) and to age 65 (YPLL65 ). RESULTS: During 1999-2010, a total of 427,005 YPLL and 55,184 YPLL65 were attributed to asbestosis (56,907 YPLL and 2,167 YPLL65 ), malignant mesothelioma (370,098 YPPL and 53,017 YPLL65 ). Overall and disease-specific asbestos-attributable total YPLL and YPLL65 and median YPLL and YPLL65 per decedent did not change significantly from 1999 to 2010. CONCLUSIONS: The continuing occurrence of asbestos-associated diseases and their substantial premature mortality burden underscore the need for maintaining prevention efforts and for ongoing surveillance to monitor temporal trends in these diseases.

Reproducibility of serology assays for pandemic influenza H1N1: collaborative study to evaluate a candidate WHO International Standard.

Haemagglutination-inhibition (HI) and virus neutralisation (VN) assays are used to evaluate immunogenicity of pandemic H1N1 vaccines; however these bioassays are poorly standardised leading to inter-laboratory variation. A candidate International Standard (IS) for antibody to H1N1 pdm virus (09/194) was prepared from pooled sera of subjects who had either recovered from H1N1 pdm infection or who had been immunised with an adjuvanted subunit vaccine prepared from reassortant virus NYMC X-179A (derived from A/California/7/2009 virus). Ten laboratories from seven countries tested the candidate IS, 09/194 and a panel of human sera by HI and VN using the A/California/7/2009 virus (six laboratories) and/or the reassortant virus NYMC X-179A (ten laboratories). As expected, the inter-laboratory variability for HI and VN assay results was high. For results of antibody tests to NYMC X-179A, the % geometric coefficient of variation (%GCV) for 09/194 between laboratories was 83% for HI and 192% for VN. For tests of all sera, the median %GCV ranged from 95 to 345% for HI (80-fold variation) and 204 to 383% for VN (109-fold variation), but for the titres relative to 09/194 the median %GCV was much reduced (HI 34-231%; VN 44-214%). For tests of antibody to the A/California/7/2009 wild type virus there were similar reductions in %GCV when 09/194 was used. These results suggest that 09/194 will be of use to standardise assays of antibody to A/California/7/2009 vaccine and 09/194 has now been established by WHO as an IS for antibody to A/California/7/2009 with an assigned potency of 1300 IU per ml.

Silicosis mortality with respiratory tuberculosis in the United States, 1968-2006.

The presence of tuberculosis (TB) in patients with silicosis increases mortality risk. To characterize silicosis-respiratory TB comortality in the United States, the authors used 1968-2006 National Center for Health Statistics multiple cause-of-death data for decedents aged ≥25 years. The authors calculated proportionate mortality ratios (PMRs) using available information on decedents' industries and occupations reported from 26 states from 1985 through 1999. Among 16,648 silicosis deaths, 2,278 (13.7%) had respiratory TB listed on the death certificate. Of silicosis-respiratory TB deaths, 1,666 decedents (73.1%) were aged ≥65 years, 2,255 (99.0%) were male, and 1,893 (83.1%) were white. Silicosis-respiratory TB deaths declined 99.5% during the study period (P < 0.001 for time-related trend), from 239.8 per year during 1968-1972 to 1.2 per year during 2002-2006, with no reported deaths in 2006. Silicosis-respiratory TB deaths reported from Pennsylvania (n = 525; 1.29 per million population), Ohio (n = 258; 0.81 per million), and West Virginia (n = 146; 2.35 per million) accounted for 40.8% of all such deaths in the United States. The highest PMR for silicosis-respiratory TB death was associated with the "miscellaneous nonmetallic mineral and stone products" industry (PMR = 73.7, 95% confidence interval: 33.8, 139.8). In the United States, 2006 marked the first year since 1968 with no silicosis-respiratory TB deaths. The substantial decline in silicosis-respiratory TB comortality probably reflects prevention and control measures for both diseases.

Quality of life following surgery for sleep disordered breathing: subtotal reduction adenotonsillectomy versus adenotonsillectomy in Australian children.

BACKGROUND: Adenotonsillectomy (AT) is indicated for children with obstructive sleep disordered breathing; however it has associated well-documented morbidity. A subtotal reduction AT has made a resurgence overseas, given a significantly reduced morbidity. This study hypothesized that full AT would provide a greater improvement in quality of life (QOL) when compared with a subtotal reduction AT (SRAT) in children with obstructive sleep disordered breathing. METHODS: This cohort study used a single surgeon consecutive series of 181 children from the database of the senior author (ASC) following full AT (n= 118) or SRAT (n= 63). QOL was measured by the Glasgow Children's Benefit Inventory (GCBI), which was mailed to parents 3 months to 2 years post-operatively. RESULTS: Ninety-one of the 155 (59%) questionnaires were returned. There was an increase in QOL for children following AT (GCBI Total =+41.5) and SRAT (GCBI Total =+49.5). A significant increase in QOL was noted for all four domains of the GCBI. The GCBI total and four domains had no statistically significant difference in the improvement of scores by the two surgical groups. CONCLUSION: In this study, an SRAT provides identical post-operative QOL outcomes to full AT when performed for sleep disordered breathing in children. This adds to the evidence that in the absence of infective episodes, SRAT can be considered as a lower risk alternative to full AT.

Serological response to trivalent inactive influenza vaccine in HIV-infected children with different immunologic status.

Influenza vaccination is usually recommended for HIV-infected children. One hundred and twenty seven HIV-infected and twenty-one HIV-uninfected children aged ≥6 months to <18 years, all of whom were naïve to influenza vaccine, were enrolled to receive an influenza Trivalent Inactivated Vaccine (TIV). In the HIV group, the post-vaccination immune response (geometric mean titer, seroconversion and seroprotection rates) correlated with their immunological status before vaccination. The HIV-infected children with no immunosuppression had comparable serological response to HIV-uninfected children. For moderately and severely immunosuppressed HIV groups, two doses of TIV resulted in greater serological responses and should be recommended in these groups.

The development of vaccine viruses against pandemic A(H1N1) influenza.

Wild type human influenza viruses do not usually grow well in embryonated hens' eggs, the substrate of choice for the production of inactivated influenza vaccine, and vaccine viruses need to be developed specifically for this purpose. In the event of a pandemic of influenza, vaccine viruses need to be created with utmost speed. At the onset of the current A(H1N1) pandemic in April 2009, a network of laboratories began a race against time to develop suitable candidate vaccine viruses. Two approaches were followed, the classical reassortment approach and the more recent reverse genetics approach. This report describes the development and the characteristics of current pandemic H1N1 candidate vaccine viruses.

Safety and immunogenicity of whole-virus, alum-adjuvanted whole-virus, virosomal, and whole-virus intradermal influenza A/H9N2 vaccine formulations.

Avian influenza H9N2 viruses are considered as a pandemic threat. We assessed the safety and immunogenicity of fourteen H9N2 vaccine formulations. A randomized, phase I trial was done in 353 adults, aged 18-82 years. Subjects received two doses of A/Hong Kong/1073/99 (H9N2) whole-virus, alum-adjuvanted whole-virus, virosomal, or intradermal whole-virus vaccine at four doses (1.7, 5, 15 or 45 microg haemagglutinin). Sera were obtained before and three weeks after each vaccination (days 0, 21, and 42) for haemagglutination-inhibition (HAI) and neutralization assays. All formulations were well tolerated. Pre-vaccination sera from subjects aged below or above 40 years had baseline antibody to H9N2 in 1% and 16% of samples. Compared to intramuscular whole-virus vaccine, alum-adjuvanted vaccine was more immunogenic, intradermal vaccine was comparable, and virosomal vaccine less immunogenic. Among subjects under 40 years, two doses (45, 15, and 5 microg) of alum-adjuvanted vaccine achieved seroprotective HAI titres in 50%, 41%, and 39% respectively, and neutralization seroconversions in 83%, 82%, and 78% of recipients. Among subjects over 40 years, one dose (45, 15, and 5 microg) of alum-adjuvanted vaccine achieved seroprotective HAI titres in 50%, 25% and 0% respectively, and neutralization seroconversions in 88%, 63% and 63% of recipients. Among immunologically naive subjects under 40 years, two doses of vaccine are required and alum-adjuvanted vaccines were most immunogenic. Among immunologically primed subjects over 40 years, one dose of whole-virus or alum-adjuvanted vaccine induced immune responses; the second dose provided less additional benefit. However, no vaccine formulation satisfied all European regulatory criteria for pandemic vaccines.

Reproducibility of serologic assays for influenza virus A (H5N1).

Hemagglutination-inhibition (HI) and neutralization are used to evaluate vaccines against influenza virus A (H5N1); however, poor standardization leads to interlaboratory variation of results. A candidate antibody standard (07/150) was prepared from pooled plasma of persons given clade 1 A/Vietnam/1194/2004 vaccine. To test human and sheep antiserum, 15 laboratories used HI and neutralization and reassortant A/Vietnam/1194/2004, A/turkey/Turkey/1/2005 (clade 2.2), and A/Anhui/1/2005 (clade 2.3.4) viruses. Interlaboratory variation was observed for both assays, but when titers were expressed relative to 07/150, overall percentage geometric coefficient of variation for A/Vietnam/1194/2004 was reduced from 125% to 61% for HI and from 183% to 81% for neutralization. Lack of reduced variability to clade 2 antigens suggested the need for clade-specific standards. Sheep antiserum as a standard did not reliably reduce variability. The World Health Organization has established 07/150 as an international standard for antibody to clade 1 subtype H5 and has an assigned potency of 1,000 IU/ampoule.

Cholesterol regulates melanogenesis in human epidermal melanocytes and melanoma cells.

Cholesterol is important for membrane stability and is the key substrate for the synthesis of steroid hormones and vitamin D. Furthermore, it is a major component of the lipid barrier in the stratum corneum of the human epidermis. Considering that steroid hormone synthesis is taking place in epidermal melanocytes, we tested whether downstream oestrogen receptor/cAMP signalling via MITF/tyrosine hydroxylase/tyrosinase/pigmentation could be possibly modulated by cholesterol. For this purpose, we utilized human primary melanocyte cell cultures and human melanoma cells with different pigmentation capacity applying immunofluorescence, RT-PCR, Western blotting and determination of melanin content. Our in situ and in vitro results demonstrated that melanocytes can synthesize cholesterol via HMG-CoA reductase and transport cholesterol via LDL/Apo-B100/LDLR. Moreover, we show that cholesterol increases melanogenesis in these cells and in human melanoma cells of intermediate pigmentation (FM55) in a time- and dose-dependent manner. Cellular cholesterol levels in melanoma cells with different pigmentation patterns, epidermal melanocytes and keratinocytes do not differ except in the amelanotic (FM3) melanoma cell line. This result is in agreement with decreasing cholesterol content versus increasing pigmentation in melanosomes. Cholesterol induces cAMP in a biphasic manner i.e. after 30 min and later after 6 and 24 h, meanwhile protein expression of oestrogen receptor beta, CREB, MITF, tyrosine hydroxylase and tyrosinase is induced after 72 h. Taken together, we show that human epidermal melanocytes have the capacity of cholesterol signalling via LDL/Apo-B100/LDL receptor and that cholesterol under in vitro conditions increases melanogenesis.

Current challenges in implementing cell-derived influenza vaccines: implications for production and regulation, July 2007, NIBSC, Potters Bar, UK.

A meeting was held at NIBSC, UK in July 2007 to discuss the implications of progress in the use of cell culture systems for the manufacture of vaccines against influenza. Issues discussed included the effect of using eggs and different cell types in strain selection, development of seed viruses to be used in production and the nature of the reagents to be used in determining vaccine potency. Future studies to progress the field were reviewed.