The First Meeting of the National Control Laboratories for Vaccines and Biologicals in the Western Pacific in 2016

Establishment of Reference Reagents for Single-Radial-Immunodiffusion Assay on the 2022/23 Seasonal Influenza Vaccine in Japan and Their Quality Validation

Potency tests for influenza vaccines are currently performed using a single-radial immunodiffusion (SRID) assay, which requires a reference antigen and anti-hemagglutinin (HA) serum as reference reagents. Reagents must be newly prepared each time a strain used for vaccine production is modified. Therefore, establishing reference reagents of consistent quality is crucial for conducting vaccine potency tests accurately and precisely. Here, we established reference reagents for the SRID assay to conduct lot release tests of quadrivalent influenza vaccines in Japan during the 2022/23 influenza season. The potency of reference antigens during storage was confirmed. Furthermore, we evaluated the cross-reactivity of each antiserum raised against the HA protein of the 2 lineages of influenza B virus toward different lineages of influenza B virus antigens to select a suitable procedure for the SRID assay for accurate measurement. Finally, the intralaboratory reproducibility of the SRID assay using the established reference reagents was validated, and the SRID reagents had sufficient consistent quality, comparable to that of the reagents used for testing vaccines during previous influenza seasons. Our study contributes to the quality control of influenza vaccines.

Report on the seventh meeting of national control laboratories for vaccines and biologicals of the WHO Western Pacific and South-East Asia member states

The Biregional Network of National Control Laboratories (NCLs) of the WHO Western Pacific and South-East Asia Regions has been meeting annually since 2018 to enhance NCLs' voluntary participation capacity. Its seventh meeting was hosted by the Korea National Institute of Food and Drug Safety Evaluation (NIFDS) of the Ministry of Food and Drug Safety (MFDS), in conjunction with the Global Bio Conference, in Seoul on September 6, 2022. Over 60 participants from seven countries, (India, Indonesia, Japan, Korea, Malaysia, the Philippines, and Vietnam) attended the meeting on-site and online. The theme of this meeting was 'Quality Control Issues and International Trends for Biologicals including Vaccines and Plasma-Derived Medicinal Products.' Three special speeches were presented on sharing the quality control system for biologicals, including NCLs' considerations in preparing the WHO Listed Authorities and sharing MFDS experiences. Furthermore, the participating NCLs shared country-specific issues related to national lot releases during the COVID-19 pandemic and acknowledged the meeting's crucial role in response preparedness for pandemic emergencies and enhancing regulatory capacity through coalitions and information exchange among NCLs. The NIFDS will cooperate closely with other Asian NCLs to enhance biological product quality control, aiming to establish regional standards and standardize test methods through collaboration.

A collaborative study to establish the second national standard for hepatitis B immunoglobulin in Korea

This study aimed to establish a second national standard for hepatitis B immunoglobulin (HBIG) that can be used for potency assays of hepatitis B and normal immunoglobulin. The candidate material was manufactured using a process approved as Good Manufacturing Practice. The freeze-dried candidate preparation was tested for physicochemical and biological properties, including pH, residual moisture, molecular size distribution, and potency. A collaborative study was performed involving four laboratories, including the National Institute of Food and Drug Safety Evaluation, as an official national control laboratory in Korea and manufacturers. The potency was calibrated against the second international standard for HBIG using two enzyme immunoassays: enzyme-linked immunosorbent assay and electrochemiluminescence immunoassay. Results from 240 assays were obtained from four laboratories, and combined potency estimates were obtained by calculating the geometric means. Intra- and inter-laboratory variability showed acceptable geometric coefficients of variation of 1.3-6.0 and 3.2-3.6%, respectively. The candidate preparation showed satisfactory stability in accelerated thermal degradation and real-time stability tests. Based on these results, the potency value of 105 IU/vial was assigned (95% confidence intervals: 100.0-109.2 IU/vial), and it was deemed suitable to serve as the Korean national standard for HBIG.

Effect of Agkistrodon halys antivenom in patients bit by green pit viper and the prognostic role of the disease - a retrospective cohort study

BACKGROUND AND AIMS

In Mainland China and Hong Kong, health authorities utilize Agkistrodon halys antivenom in the treatment of patients who sustained bites from green pit vipers. However, the treatment benefit of Agkistrodon halys antivenom among such patients is still controversial. The purpose of this study is to evaluate the coagulation parameters normalization time of Agkistrodon halys antivenom in patients who sustained green pit viper bites and explore independent risk factors of patient prognosis.

METHODS

Data were extracted from the Donghua Hospital Information System. Comparison of the two groups of patients - who used antivenom (GPUA) and who did not use antivenom (GPNUA) were performed using stratified analysis, univariate and multivariate ordered logistic regression models to evaluate the coagulation parameters normalization time. Univariate and multivariate ordered logistic regression models were used to explore independent risk factors of patient prognosis.

RESULTS

Between the GPUA and GPNUA groups, there is no significant difference in the coagulation parameters normalization time with the treatment of Agkistrodon halys antivenom. GPNUA consumed more cryoprecipitate and platelets and had a lower cost. The patient's severity of the bite, first coagulation profile, and dosages of fresh frozen plasma, platelet, and red cell suspension was found to be risk factors for the normalization time of coagulation parameters.

CONCLUSIONS

The therapeutic effect of Agkistrodon halys antivenom in green pit vipers bite patients is not quite satisfying. In addition, more attention should be paid to the first coagulation profile, blood clotting factors indices, platelet count (PLT), and hemoglobin when treating such patients.

Determination of the potency of a cell-based seasonal quadrivalent influenza vaccine using a purified primary liquid standard

In Japan, the practical application of completely cell-based seasonal influenza vaccines is under consideration. Considering the good correlation between the immunogenicity of egg-based influenza vaccines and the hemagglutinin (HA) content determined by the single radial immunodiffusion (SRD) assay, we determined the potency of the first cell-based quadrivalent vaccine experimentally generated in Japan using the SRD assay in this study. A primary liquid standard (PLS) and reference antigen were generated from the purified vaccine virus, and a sheep antiserum was produced against the HA of the vaccine virus. Since the purity of the PLS affects the reliability of vaccine potency testing, the purification steps are significant. We successfully prepared a purified PLS nearly free of cell debris. The HA content in the PLS was first estimated from the total amount of viral protein and the percentage of HA content determined by SDS-PAGE analysis. The HA content in the reference antigen was calibrated to that in the PLS via the SRD assay. The vaccine potency, that is, the HA content in each vaccine, was finally measured using the corresponding reference antigen. Ultimately, the measured vaccine potency of the monovalent vaccine was similar to that of the quadrivalent vaccine.

A Collaborative Study to Establish the Second Korean National Reference Standard for Snake Venom

In 2015, a candidate for the second national reference standard (NRS) of Gloydius snake venom was produced to replace the first NRS of Gloydius snake venom. In the present study, the potencies of the candidate were determined by a collaborative study, and the qualification of the candidate was estimated. The potencies of the candidate were determined by measuring the murine lethal titers and lapine hemorrhagic titers of venom against the regional working reference standard (RWRS) for antivenom using the methods described in the previous report for the first NRS of Gloydius snake venom. Three Korean facilities contributed data from a total of 30 independent assays. Subsequently, two foreign national control research laboratories contributed to this collaborative study. The results were calculated using the Reed-Muench method for lethality and determined using a mixed-effects model for hemorrhage. The general common potencies of the lethal and hemorrhagic titers were obtained from the results of the 30 tests performed at three Korean facilities. The results are expressed in micrograms for 1 test dose (TD) with a 95% confidence interval as follows: a lethal titer of 90.13 μg/TD (95% confidence interval = 87.39~92.86 μg) and a hemorrhagic titer of 10.80 μg/TD (95% confidence interval = 10.46~11.14 μg). In addition, the candidate preparation showed good quality evaluation according to the results of the quality estimation of the candidate and is judged to be suitable to serve as the Korean NRS for snake venom. In conclusion, the second NRS of Gloydius snake venom was established in this study and will be used for national quality control, including a national lot release test of Korean antivenom products.

The 2nd Meeting of National Control Laboratories for Vaccines and Biologicals in the Western Pacific

The Second Meeting of the National Control Laboratories for Vaccines and Biologicals in the Western Pacific, was jointly organized by the National Institute of Food and Drug Safety Evaluation of the Ministry of Food and Drug Safety in the Republic of Korea, and by the World Health Organization Regional Office for the Western Pacific.

In the National Lot Release Systems session countries including Canada, China, Japan, Malaysia, Vietnam, and the Republic of Korea, all shared information on their current Lot Release Systems, including current practices and developments in risk-based official lot release of vaccines.

In the session on Quality Control of Blood Products, experts from the National Institute for Biological Standards and Control shared quality control and research results for; blood coagulation factor VIII products, and the measurement of procoagulant activity in immunoglobulin products. Representatives from Japan proposed a regional collaborative study to test aggregated immunoglobulin free from complement activity. A cell-based Japanese encephalitis vaccine potency assay was proposed by representatives from Korea and they also called for voluntary participation of other National Control Laboratories in a collaborative study, on the first Korean Gloydius anti-venom standard. Participants agreed in general to continue communicating, and coordinate presentation of the study results.

Measles control in Australia - threats, opportunities and future needs

Control of measles was the focus of a national workshop held in 2015 in Sydney, Australia, bringing together stakeholders in disease control and immunisation to discuss maintaining Australia's measles elimination status in the context of regional and global measles control. The global epidemiology of measles was reviewed, including outbreaks in countries that have achieved elimination, such as the Disneyland outbreak in the United States and large outbreaks in Sydney, Australia. Transmission of measles between Australia and New Zealand occurs, but has not been a focus of control measures. Risk groups, the genetic and seroepidemiology of measles as well as surveillance, modelling and waning vaccine-induced immunity were reviewed. Gaps in policy, research and practice for maintaining measles elimination status in Australia were identified and recommendations were developed. Elimination of measles globally is challenging because of the infectiousness of measles and the need for 2-dose vaccine coverage rates in excess of 95% in all countries to achieve it. Until this occurs, international travel will continue to permit measles importation from endemic countries to countries that have achieved elimination. When measles cases are imported, failure to diagnose and isolate cases places the health system at risk of measles outbreaks. Vaccine funding models can result in gaps in vaccine coverage for adults and migrants. Australia introduced a whole-of-life immunisation register in 2016 and catch-up vaccination for at-risk communities, which will improve measles control. Research on diagnosis, immunology, case management and modelling of vaccination strategies are important to ensure continued control of measles.