Persistent efficacy of live attenuated hepatitis A vaccine (H2-strain) after a mass vaccination program

Background Live attenuated hepatitis A vaccine （ H2 strain） is widely applied in prevention of hepatitis A epidemic in China and other countries now. It is essential to observe and confirm the vaccine immune efficacy, population antibody level and its persistent efficacy after mass immunization. Methods A total of 220 children with negative anti-HAV antibody （ aged 1-3 years） were taken for follow-up assay to observe seroconversion and geometric mean titre（GMT） level 2 months, 12 months, 6 years, and 10 years after inoculation. Another survey sampled from subjects of different age groups （3, 6, 9, 15, 18, 25 and 35 years） to compare anti-HA antibody positive rate before and after inoculation performed 10 years previously. Epidemiological observations were taken for 10 years to evaluate the relationship between vaccine coverage and hepatitis A morbidity. Serum antibody to HAV was detected by enzyme linked immunoassay （ELISA, calibrated by WHO international reference） and ABBOTY Axsym HAVAB microparticle enzyme immunoassay. Results Seroconversion in follow-up assay 2 months and 10 years after inoculation was 98.6% and 80. 2% respectively. For children, the vaccination anti-HA antibody positive rates were significantly different before and after 10 years, 7.69% cf 70.45% （aged 3 years） and 52. 58% cf 71.78% （aged 18 years）. When vaccine coverage rose from 57% to 74%, there were no any HA epidemics. When vaccine coverage reached 85%, there were no any HA cases. With vaccine coverage between 85% and 91%, there were no any HA cases in cohorts from the age of 1 year to 15 years during the 10 years. Conclusions Live attenuated hepatitis A vaccine has an obvious long-term effectiveness in prevention and control of HA epidemics through mass vaccination.

Factors associated with mobile phone ownership and potential use for rabies vaccination campaigns in southern Malawi

Background:Rabies is a fatal but preventable viral disease,which causes an estimated 59000 human deaths globally every year.The vast majority of human rabies cases are attributable to bites from infected domestic dogs and consequently control of rabies in the dog population through mass vaccination campaigns is considered the most effective method of eliminating the disease.Achieving the WHO target of 70%vaccination coverage has proven challenging in low-resource settings such as Sub Saharan Africa,and lack of public awareness about rabies vaccination campaigns is a major barrier to their success.In this study we surveyed communities in three districts in Southern Malawi to assess the extent of and socio-economic factors associated with mobile phone ownership and explore the attitudes of communities towards the use of short message service(SMS)to inform them of upcoming rabies vaccination clinics.Methods:This study was carried out between 1 October–3 December 2018 during the post-vaccination assessment of the annual dog rabies campaign in Blantyre,Zomba and Chiradzulu districts,Malawi.1882 questionnaires were administered to households in 90 vaccination zones.The surveys gathered data on mobile phone ownership and use,and barriers to mobile phone access.A multivariable regression model was used to understand factors related to mobile phone ownership.Results:Most survey respondents owned or had use of a mobile phone,however there was evidence of an inequality of access,with higher education level,living in Blantyre district and being male positively associated with mobile phone ownership.The principal barrier to mobile phone ownership was the cost of the phone itself.Basic feature phones were most common and few owned smartphones.SMS was commonly used and the main reason for not using SMS was illiteracy.Attitudes to receiving SMS reminders about future rabies vaccination campaigns were positive.Conclusions:The study showed a majority of those surveyed have the use of a mobile phone and most mobile phone owners indicated they would like to receive SMS messages about future rabies vaccination campaigns.This study provides insight into the feasibility of distributing information about rabies vaccination campaigns using mobile phones in Malawi.

Comprehensive narrative review of real-world COVID-19 vaccines:viewpoints and opportunities

Currently,people all over the world have been affected by coronavirus disease 2019(COVID-19).Fighting against COVID-19 is the top priority for all the countries and nations.The development of a safe and effective COVID-19 vaccine is considered the optimal way of ending the pandemic.Three hundred and 44 vaccines were in development,with 149 undergoing clinical research and 35 authorized for emergency use as to March 15 of 2022.Many studies have shown the effective role of COVID-19 vaccines in preventing SARS-CoV-2 infections as well as serious and fatal COVID-19 cases.However,tough challenges have arisen regarding COVID-19 vaccines,including long-term immunity,emerging COVID-19 variants,and vaccine inequalities.A systematic review was performed of recent COVID-19 vaccine studies,with a focus on vaccine type,efficacy and effectiveness,and protection against SARS-CoV-2 variants,breakthrough infections,safety,deployment and vaccine strategies used in the real-world.Ultimately,there is a need to establish a unified evaluation standard of vaccine effectiveness,monitor vaccine safety and effectiveness,along with the virological characteristics of SARS-CoV-2 variants;and determine the most useful booster schedule.These aspects must be coordinated to ensure timely responses to beneficial or detrimental situations.In the future,global efforts should be directed toward effective and immediate vaccine allocations,improving vaccine coverage,SARS-CoV-2 new variants tracking,and vaccine booster development.