National Vaccination Campaign Research Articles

Trends in Adult and Elderly Vaccination: Focus on Vaccination Practices in Tunisia and Morocco.

Vaccine preventable diseases (VPDs) are a prevailing concern among the adult population, despite availability of vaccines. Unlike pediatric vaccination programs, adult vaccination programs lack the required reach, initiative, and awareness. Clinical studies and real-world data have proven that vaccines effectively reduce the disease burden of VPDs and increase life expectancy. In Tunisia and Morocco, the national immunization program (NIP) focuses more on pediatric vaccination and have limited vaccination programs for adults. However, some vaccination campaigns targeting adults are organized. For example, influenza vaccination campaigns prioritizing at risk adults which includes healthcare professionals, elderly, and patients with comorbidities. Women of childbearing age who have never been vaccinated or whose information is uncertain are recommended to receive tetanus vaccination. Tunisia NIP recommends rubella vaccine mainly for women of childbearing age, while in Morocco, national vaccination campaigns were organized for girls and women (up to 24 years of age) to eliminate rubella. Further, travelers from both countries are recommended to follow all requirements and recommendations in the travel destination. The objective of this manuscript is to provide an overview of the global disease burden of common VPDs including (but not limited to) meningococcal diseases, pneumococcal diseases, hepatitis, and influenza. The review also provides an overview of clinical data and guidelines/recommendations on adult vaccination practices, with special focus on Tunisia and Morocco. Some European and North American countries have concrete recommendations and strategies for adult vaccination to keep the VPDs in check. In Morocco and Tunisia, although, there are sporadic adult vaccination initiatives, the efforts still need upscaling and endorsements to boost vaccination awareness and uptake. There is a need to strengthen strategies in both countries to understand the disease burden and spread awareness. Additional studies are needed to generate economic evidence to support cost-effectiveness of vaccines. Integration of private and public healthcare systems may further improve vaccination uptake in adults.

EPH140 SARS-COV-2 Breakthrough Infections Among the Healthcare Workers Post-Vaccination with ChAdOx1 nCoV-19 Vaccine in the South Indian State of Kerala

The national COVID-19 vaccination campaigns in India, prioritized healthcare workers to be vaccinated with ChAdOx1 nCoV-19 (AZD1222). So, we aimed to ascertain the effectiveness of ChAdOx1 nCoV-19 vaccine among the healthcare workers by characterizing the breakthrough infections which occurred 14 days after the second dose of the vaccine.

Investigating COVID-19 Vaccine Impact on the Risk of Hospitalisation through the Analysis of National Surveillance Data Collected in Belgium.

The national vaccination campaign against SARS-CoV-2 started in January 2021 in Belgium. In the present study, we aimed to use national hospitalisation surveillance data to investigate the recent evolution of vaccine impact on the risk of COVID-19 hospitalisation. We analysed aggregated data from 27,608 COVID-19 patients hospitalised between October 2021 and February 2022, stratified by age category and vaccination status. For each period, vaccination status, and age group, we estimated risk ratios (RR) corresponding to the ratio between the probability of being hospitalised following SARS-CoV-2 infection if belonging to the vaccinated population and the same probability if belonging to the unvaccinated population. In October 2021, a relatively high RR was estimated for vaccinated people > 75 years old, possibly reflecting waning immunity within this group, which was vaccinated early in 2021 and invited to receive the booster vaccination at that time. In January 2022, a RR increase was observed in all age categories coinciding with the dominance of the Omicron variant. Despite the absence of control for factors like comorbidities, previous infections, or time since the last administered vaccine, we showed that such real-time aggregated data make it possible to approximate trends in vaccine impact over time.

Framing policies to mobilize citizens' behavior during a crisis: Examining the effects of positive and negative vaccination incentivizing policies

AbstractThe COVID‐19 pandemic has highlighted the issue of mobilization policies, that is, government practices directed at making the mass public voluntarily perform various behaviors for the collective benefit during a crisis. As COVID‐19 vaccinations became accessible, governments faced the challenge of mass vaccination mobilization in order to achieve herd immunization. Aiming to effectively realize this goal, policy designers and regulators worldwide considered various mobilizing tools for vaccination compliance, including rewards and penalties, as they targeted vaccine opposers and hesitators, while trying to avoid the crowding‐out effect among individuals who were intrinsically motivated to get vaccinated. However, the unique circumstances of the Coronavirus pandemic may have eliminated the crowding‐out effect. Thus, our study explored the effect of regulation in the form of positive and negative incentivizing tools (i.e., rewards and penalties) during the coronavirus pandemic on vaccination intentions of 1184 Israeli citizens, prior to the national vaccination campaign. Results indicate that (1) both negative and positive incentives have a similar positive effect on individuals who declare they will not get vaccinated and those who hesitate to get the shot; (2) both positive and negative incentives induce the crowding‐out effect; and (3) negative incentives generate a larger crowding‐out effect in individuals who report preliminary intentions to get vaccinated, compared to positive ones. This emphasizes the need to avoid the crowding‐out effect during the current and similar crises, and suggests considering applying a gradual and adaptive policy design in order to maximize regulatory efficacy and compliance.

CRITICAL ANALYSIS OF THE CAT’S ROLE IN THE EPIDEMIOLOGY OF RABIES

Rabies is a fatal zoonosis of world importance that in many aspects is still neglected. Due to national vaccination campaigns for dogs and cats, there has been a drastic reduction in the number of cases of human rabies transmitted by dogs. However, due to species peculiarities, the cat can act as an important link in the epidemiological chain of rabies. Thus, this study aimed to evaluate Brazilian data on canine and feline rabies surveillance to determine the importance of the cat in the current context of rabies epidemiology. In Brazil, recent cases of human rabies transmitted by cats have been reported, showing the importance of this species in the epidemiological chain of the disease.

To Determine the Clinical Efficacy of COVID Vaccine in Post Vaccinated Individuals with Severe Pneumonia in Preventing ICU Mortality in a COVID Designated Tertiary Care Centre: A Retrospective Study

Background: The "Severe Acute Respiratory Syndrome Coronavirus 2 disease has caused globally a challenging and threatening pandemic (COVID-19), with massive health and economic losses [1]. In India national vaccination campaigns kick started officially on January 16, 2021, and the vaccines were prioritized for frontline workers and susceptible groups. Individual vaccination can prevent or minimise a number of outcomes, including lab confirmed infection, symptomatic illness, infectivity rate, or a combination of these [2-3]. India had initially approved two vaccines under the trade name Covishield and Covaxin against COVID. Aim: Demonstrate the efficacy of a single / two -dose schedule of COVID vaccine in the prevention of ICU mortality.
 Methods: In this retrospective study, we included all COVID 19 confirmed patients who were admitted in covid designated ICU from March 15 to July 31 2021. Demographic, clinical, laboratory and radiological data were collected from all patients received in ICU. Primary outcome was to assess the mortality outcome in vaccinated COVID patients. Secondary outcome measured were to find an association between severity of the pneumonia and comorbidities, PaO2/Fio2 ratio, Neutrophil lymphocyte ratio, D dimer and CT severity score.
 Results: 319 patients were enrolled in the study. 252 patients were not vaccinated.59 had received the first dose and 8 patients had received both the doses. The mortality among vaccinated patients were less compared to nonvaccinated and significant (p value 0.030). Mortality among single and double dose vaccinated patients couldn’t be made out because only 8 patients had received both the doses. Among the demographic profile, difference in age between vaccinated and unvaccinated was statistically significant. (64.39 ±11.916/ 54.18±14.124 p<.001. Among comorbidities hypertension, diabetes, obesity was associated with significant mortality. Admission saturation and mean PaO2/FiO2 ratio were high among vaccinated and significant. Neutrophil lymphocyte ratio, D dimer CT severity score were high among non vaccinated compared to vaccinated. There is no difference in mode of oxygen delivery in both vaccinated and non vaccinated patient. Days of ICU stayal was less among vaccinated.
 Conclusion: Effectiveness of vaccine against SARS-CoV-2 infection after the first dose of immunisation is convincingly evident. However second dose of immunization should be continued to attain total protection.

Human papillomavirus vaccination available for boys also; information for oral healthcare providers

Recently, the Dutch National Immunization Programme has started to offer the human papillomavirus (HPV) vaccination to boys as well as girls from the age of 10. The vaccine protects against long-term HPV infection, which can lead to cervical, anogenital and oropharyngeal cancer. Besides malignant disorders, a HPV infection can also lead to certain disorders of the skin and oral cavity. Since the national HPV vaccination campaign has probably resulted in more awareness among patients about the relation between HPV and oropharyngeal cancer, patients may consult oral healthcare professionals with questions about HPV infection. Oral healthcare professionals are thus able to play a role in preventing HPV related disorders by counseling their patients on HPV. They can also contribute to early diagnosis of HPV related oral and oropharyngeal disorder, although the possibility of detecting oropharyngeal cancer during routine dental examination is limited.

National Scale Real-Time Surveillance of SARS-CoV-2 Variants Dynamics by Wastewater Monitoring in Israel.

In this report, we describe a national-scale monitoring of the SARS-CoV-2 (SC-2) variant dynamics in Israel, using multiple-time sampling of 13 wastewater treatment plants. We used a combination of inclusive and selective quantitative PCR assays that specifically identify variants A19/A20 or B.1.1.7 and tested each sample for the presence and relative viral RNA load of each variant. We show that between December 2020 and March 2021, a complete shift in the SC-2 variant circulation was observed, where the B.1.1.7 replaced the A19 in all examined test points. We further show that the normalized viral load (NVL) values and the average new cases per week reached a peak in January 2021 and then decreased gradually in almost all test points, in parallel with the progression of the national vaccination campaign, during February–March 2021. This study demonstrates the importance of monitoring SC-2 variant by using a combination of inclusive and selective PCR tests on a national scale through wastewater sampling, which is far more amendable for high-throughput monitoring compared with sequencing. This approach may be useful for real-time dynamics surveillance of current and future variants, such as the Omicron (BA.1, BA.2) and other variants.

Impact of national Covid-19 vaccination Campaign, South Korea

BackgroundWe evaluate the overall effectiveness of the nationwide vaccination campaign using ChAdOx1 nCoV-19, BNT162b2, mRNA-1273, and Ad26.COV2.S vaccines in preventing Covid-19 in South Korea. MethodsThe National Surveillance System with the National Immunization Registry were linked to form a large-linked database for assessment. Age-adjusted incidence of SARS-CoV-2 infection, severe disease, and death by vaccination status are calculated. Weekly vaccine effectiveness was calculated based on incidence rate ratio (IRR) between fully-vaccinated and unvaccinated persons, as: IRR = incidence rate of vaccinated / incidence rate of unvaccinated. We estimate the cumulative SARS-CoV-2 outcome overtime comparing the observed case with predicted cases without vaccination. ResultsAge-adjusted incidence in unvaccinated persons (5.69 per 100,000 person-day) was 2.7 times the rate in fully vaccinated (2.13 per 100,000 person-day) persons, resulting effectiveness against SARS-CoV-2 infection of 63%. Vaccine effectiveness against severe disease and death were 93% and 95%, respectively. Between March and October 2021, estimated Covid-19 related outcomes averted by vaccinations were: 46,508 infections, 3,424 severe diseases, and 718 deaths. ConclusionsWe found significant protection for national Covid-19 vaccination campaign against Covid-19 severe disease, and death in target populations, but there was an unexpected decreased protection against SARS-CoV-2 infection, highlighting the importance of continued surveillance and assessment.

Left Behind: The Multiple Impacts of Covid-19 on Forcibly Displaced People

To better understand vaccination barriers and the impacts of Covid-19 on forcibly displaced persons (FDPs, i.e. refugees, and internally displaced persons (IDPs)), World Vision International carried out a multi-country survey of refugee populations in Colombia, Peru, Brazil, Uganda, the Democratic Republic of the Congo (DRC), Jordan, and Turkey, and IDPs in Venezuela. The survey found that a combination of barriers led to FDPs falling through the gaps of national Covid-19 vaccination campaigns, despite their heightened vulnerability to Covid-19 infection and transmission. Only one person out of the 1,914 FDPs surveyed reported receiving a Covid-19 vaccine. The survey also highlighted the significant indirect impacts of the pandemic on forcibly displaced families, and children specifically, with the socioeconomic aftershocks of the Covid-19 pandemic worsening displaced children’s deprivations across health and nutrition, protection support, and education.

Social media sentiment analysis to monitor the performance of vaccination coverage during the early phase of the national COVID-19 vaccine rollout

Background and objectiveSocial media sentiment analysis based on Twitter data can facilitate real-time monitoring of COVID-19 vaccine-related concerns. Thus, the governments can adopt proactive measures to address misinformation and inappropriate behaviors surrounding the COVID-19 vaccine, threatening the success of the national vaccination campaign. This study aims to identify the correlation between COVID-19 vaccine sentiments expressed on Twitter and COVID-19 vaccination coverage, case increase, and case fatality rate in Indonesia. MethodsWe retrieved COVID-19 vaccine-related tweets collected from Indonesian Twitter users between October 15, 2020, to April 12, 2021, using Drone Emprit Academic (DEA) platform. We collected the daily trend of COVID-19 vaccine coverage and the rate of case increase and case fatality from the Ministry of Health (MoH) official website and the KawalCOVID19 database, respectively. We identified the public sentiments, emotions, word usage, and trend of all filtered tweets 90 days before and after the national vaccination rollout in Indonesia. ResultsUsing a total of 555,892 COVID-19 vaccine-related tweets, we observed the negative sentiments outnumbered positive sentiments for 59 days (65.50%), with the predominant emotion of anticipation among 90 days of the beginning of the study period. However, after the vaccination rollout, the positive sentiments outnumbered negative sentiments for 56 days (62.20%) with the growth of trust emotion, which is consistent with the positive appeals of the recent news about COVID-19 vaccine safety and the government's proactive risk communication. In addition, there was a statistically significant trend of vaccination sentiment scores, which strongly correlated with the increase of vaccination coverage (r = 0.71, P<.0001 both first and second doses) and the decreasing of case increase rate (r = -0.70, P<.0001) and case fatality rate (r = -0.74, P<.0001). ConclusionsOur results highlight the utility of social media sentiment analysis as government communication strategies to build public trust, affecting individual willingness to get vaccinated. This finding will be useful for countries to identify and develop strategies for speed up the vaccination rate by monitoring the dynamic netizens' reactions and expression in social media, especially Twitter, using sentiment analysis.

SARS-COV-2 IgG positivity in vaccinated and non-vaccinated Chilean children: a national cross-sectional study in schools

COVID-19 vaccination of children is gaining global support (Committee on Infectious Diseases, 2022), and data on immunogenicity and efficacy/effectiveness are increasing (Walter et al., 2022; Frenck et al., 2021; Han et al., 2021). Chile has rapidly advanced in a national vaccination campaign for children: as of February 17, 2022, 79% of children aged 3–17 years have been fully vaccinated (Ministerio de Salud Chile, 2022). Children aged 12–17 years have been vaccinated since June 22, 2021, with the mRNA Pfizer/BioNTech vaccine, followed weeks later by children aged 6–11 years, who received the inactivated Sinovac vaccine.

The national COVID-19 vaccination campaign targeting the extremely vulnerable: the Florence Medical Oncology Unit experience in patients with cancer

BackgroundInternational and national oncology societies had released recommendations in favor of COVID-19 vaccination in cancer patients. In the context of the national vaccination campaign targeting the so called extremely vulnerable, we aimed to assess the safety and efficacy of the mRNA vaccines in a cohort of 623 patients. MethodsBetween March 26 and April 04, 2021, the Pfizer and BioNTech BNT162b2 mRNA and the Moderna mRNA-1273 vaccines were given as a two-dose prime-boost regimen. Starting on September 25th 2021 a third dose was offered to patients in whom a suboptimal immunogenicity with COVID-19 vaccination could be expected. Safety assessments were performed by phone call 7 days after each dose. Electronic health records were accessed to review demographic information, disease history, treatment detail, and outcome events of participants patients’. FindingsNo toxicities were reported in 63.7%, 54%, and in 48.7% patients with cancer after each dose. Mild-to-moderate pain at the injection site was the most commonly adverse event. After the second dose, 46% of the 610 patients reported toxicity, with more systemic side-effects observed. Fever was reported in 45% of patients, with a temperature ≥ 38 °C in 21.4% of them. Of the 335 patients receiving a third vaccine dose, 51% reported toxicity, with 13% of patients reporting more than one effect. Logistic regression analysis reported mixed results, with limited variables or categories reporting a significant odd ratio. The type of vaccine reported a significant value at first dose (OR = 0.12; CI 0.52, 0.26; p = 0.00). Thirty-four cases of COVID-19 infection were reported with only one patient requiring a short-term hospitalization for monitoring. InterpretationThe safety profile of the mRNA vaccines does not raise any specific concerns and support prioritization of vaccination for cancer patients.

THE ROLE OF SOCIAL MEDIA AS A SOURCE OF COVID-19 VACCINATION INFORMATION

This research is based on the implementation of a national vaccination campaign to prevent the transmission of Covid-19 in Indonesia, and the presence of social media can shorten the government's target in achieving the national target of 181.5 million people in Indonesia. This study uses qualitative research with a systematic literature review in uncovering research questions. The results of the study conclude that social media plays a very important role in campaigning for the government's national Covid-19 vaccination program and the form of delivery on social media using images of officials including the president plays a very important role in influencing the public to participate in the national vaccination program.

The first 30 days of COVID-19 vaccination in Cameroon: achievements, challenges, and lessons learned

IntroductionCameroon's national vaccination campaign was launched on April 12, 2021, amid a nationwide outbreak of COVID-19 with two types of vaccines. This study provides preliminary evidence to assess early outputs of the COVID-19 vaccination response strategy implementation.Methodsa cross-sectional study was conducted from April 12, 2021, to May 11, 2021, and data on COVID-19 vaccination were reviewed from the Ministry of Public Health database. Descriptive statistical analyses were conducted.Resultsthirty days after the introduction of COVID-19 vaccines, just about five percent of the target population was vaccinated. Women represented one-third of the people vaccinated regardless of age and health conditions. Although AEFI reported were minor and scanty with both vaccines, most of the vaccinated did not come back for their second dose. There was a need to build confidence among eligible beneficiaries to expand the benefits of vaccination to control the current pandemic.Conclusionthe country was still far below the target, which was worrisome given that vaccine uptake was slow. Also, 391 200 doses of the Covishield were at risk of expiration in August 2021. This study offers insights into those early efforts contributing to significant discussions about the approaches to improve service delivery and vaccine uptake.

Association of SARS-CoV-2 Vaccinations with SARS-CoV-2 Infections, ICU Admissions and Deaths in Greece.

The available coronavirus disease 2019 (COVID-19) vaccines have shown their effectiveness in clinical trials. We aimed to assess the real-world effects of SARS-CoV-2 vaccinations in Greece. We combined national data on vaccinations, SARS-CoV-2 cases, COVID-19-related ICU admissions and COVID-19-related deaths. We observed 3,367,673 vaccinations (30.68% of the Greek population), 278,821 SARS-CoV-2 infections and 7401 COVID-19-related deaths. The vaccination rate significantly increased from week 2 to week 6 by 85.70%, and from week 7 to 25 by 15.65%. The weekly mean of SARS-CoV-2 cases, COVID-19 ICU patients and COVID-19 deaths markedly declined as vaccination coverage accumulated. The rate of SARS-CoV-2 cases increased significantly from week 2 to week 13 by 16.15%, while from weeks 14–25 the rate decreased significantly by 13.50%. The rate of COVID-19-related ICU admissions decreased significantly by 7.41% from week 2 to week 4, increased significantly by 17.22% from weeks 5–11, then decreased significantly from weeks 17–20, by 11.99%, and from weeks 21–25, by 16.77%. The rate of COVID-19-related deaths increased significantly from week 2 to week 15 by 12.08% and decreased significantly by 16.58% from weeks 16–25. The data from this nationwide observational study underline the beneficial impact of the national vaccination campaign in Greece, which may offer control of the SARS-CoV-2 pandemic.

Effectiveness of mRNA BNT162b2 Vaccine 6 Months after Vaccination among Patients in Large Health Maintenance Organization, Israel

Israel experienced a new wave of coronavirus disease during June 2021, six months after implementing a national vaccination campaign. We conducted 3 discrete analyses using data from a large health maintenance organization in Israel to determine whether IgG levels of fully vaccinated persons decrease over time, describe the relationship between IgG titer and subsequent PCR-confirmed infection, and compare PCR-confirmed infection rates by period of vaccination. Mean IgG levels steadily decreased over the 6-month period in the total tested population and in all age groups. An inverse relationship was found between IgG titer and subsequent PCR-positive infection. Persons vaccinated during the first 2 months of the campaign were more likely to become infected than those subsequently vaccinated. The vaccinated group >60 years of age had lower initial IgG levels and were at greater risk for infection. The findings support the decision to add a booster vaccine for persons >60 years of age.

SARS-CoV-2 antibody seroprevalence in Lebanon: findings from the first nationwide serosurvey

BackgroundLebanon, a small country in the Middle East, remains severely affected by the COVID-19 pandemic. Seroprevalence surveys of anti-SARS-CoV-2 antibodies provide accurate estimates of SARS-CoV-2 infection and hence evaluate the extent of the pandemic. The present study aimed to evaluate the prevalence of SARS-CoV-2 antibodies in Lebanon and to compare the estimated cumulative number of COVID-19 cases with the officially registered number of laboratory-confirmed cases up to January 15, 2021.MethodsA nationwide population-based serosurvey study was conducted in Lebanon between December 7, 2020, and January 15, 2021, before the initiation of the national vaccination program. The nCOVID-19 IgG & IgM point-of-care (POCT) rapid test was used to detect the presence of anti-SARS-COV-2 immunoglobulin G (IgG) in the blood. Seroprevalence was estimated after weighting for sex, age, and area of residence and adjusting for the test performance.ResultsOf the 2058 participants, 329 were positive for IgG SARS-COV-2, resulting in a crude seroprevalence of 16.0% (95% CI 14.4–17.6). The weighed seroprevalence was 15.9% (95% CI of 14.4 and 17.4). After adjusting for test performance, the population weight-adjusted seroprevalence was 18.5% (95% CI 16.8–20.2). This estimate implies that 895,770 individuals of the general population were previously infected by COVID-19 up to January 15, 2021 in Lebanon. The overall estimated number of subjects with previous SARS-CoV-2 infection was three times higher than the officially reported cumulative number of confirmed cases. Seroprevalence was similar across age groups and sexes (p-value > 0.05). However, significant differences were revealed across governorates.ConclusionsOur results suggest that the Lebanese population is still susceptible to SARS-CoV-2 infection and far from achieving herd immunity. These findings represent an important contribution to the surveillance of the COVID-19 pandemic in Lebanon and to the understanding of how this virus spreads. Continued surveillance for COVID-19 cases and maintaining effective preventive measures are recommended to control the epidemic spread in conjunction with a national vaccination campaign to achieve the desired level of herd immunity against COVID-19.

Acceptance towards COVID-19 vaccine: A cross-sectional study in the Dominican Republic.

Introduction: The Coronavirus Disease 2019 (COVID-19) pandemic has hit globally, both economically and in the collective health, leaving irreparable human losses. In addition to preventive measures such as the use of masks and physical distancing to mitigate the ravages of the pandemic, the method of immunization through vaccines has been applied, the health cabinet of the Dominican Republic (DR) began with the national vaccination campaign against COVID-19 “Vacúnate RD”, to establish a quicker herd immunity and thus reduce morbidity and mortality. Objective: To determine the acceptance of the population regarding the vaccination process and the proposal of a third dose by the Public Health authorities in the DR. Methods: A descriptive, prospective, cross-sectional study, carried out in a 10-day collection period, which consisted of an online survey with 20 questions, divided into 3 sections and written in Spanish, the official language of the country. Results: With a total of 1096 valid answers for the statistical analysis, regarding the immunization schedule, 55.9% consider that it should not be mandatory. At the time of the survey, 6.7% had not been applied any dose from the vaccine, 7.6% had the first dose, 81.9% (n=898) had completed their scheme with the second dose, and 41 participants reported having received the third dose; the most applied vaccines among those surveyed were Sinovac (68.2%, n=747), AstraZeneca (19.6%, n=215) and Pfizer (3.8%, n=42). 41.1% (n=451) responded affirmatively to the idea of an eventual application of a third dose vaccine, while 31.5% do not feel safe to apply said, "booster dose" and 27.4% responded negatively to this idea. Conclusion: In general, an acceptance was observed in the study population of getting the vaccine against COVID-19, trusting its protective effects, although there is still a high percentage of people who expressed doubts regarding the idea proposed by the health authorities in the DR about completing the third dose as a reinforcement of the immunization scheme already established worldwide by the relevant health organizations.

Produce Japanese Encephalitis standard antiserum of strain Nakayama for vaccine quality control

Japanese Encephalitis vaccine has contributed to repel Japanese Encephalitis in young children in the national vaccination campaign. To qualitatively evaluate the protective efficiency of Japanese Encephalitis vaccine, a standard antiserum used as a positive control was performed in parallel with testing samples. A study was organized at National Institute for Control of Vaccines and Biologicals (NICVB) as following. Anti-sera were produced by 2-dose-injection of national standard vaccine to 28-day-old white mice, weighing 11- 13g. After blood collection and serum separation, the PRNT50 neutralizing antibody potency was evaluated in parallel with international standard antisera from NIBSC and antisera from Vabiotech manufacturer. Antiserum lot 0118 was produced with a neutralizing antibody potency PRNT50 of 1.74 to ensure criteria of a positive control standard for performing Japanese Encephalitis vaccine potency test.