Novel coronavirus mutations: Vaccine development and challenges.

The ongoing global pandemic of novel coronavirus pneumonia (COVID-19) caused by the SARS-CoV-2 has a significant impact on global health and economy system. In this context, there have been some landmark advances in vaccine development. Over 100 new coronavirus vaccine candidates have been approved for clinical trials, with ten WHO-approved vaccines including four inactivated virus vaccines, two mRNA vaccines, three recombinant viral vectored vaccines and one protein subunit vaccine on the "Emergency Use Listing". Although the SARS-CoV-2 has an internal proofreading mechanism, there have been a number of mutations emerged in the pandemic affecting its transmissibility, pathogenicity and immunogenicity. Of these, mutations in the spike (S) protein and the resultant mutant variants have posed new challenges for vaccine development and application. In this review article, we present an overview of vaccine development, the prevalence of new coronavirus variants and their impact on protective efficacy of existing vaccines and possible immunization strategies coping with the viral mutation and diversity.

Emergence of a young case infected with avian influenza A (H5N6) in Anhui Province, East China during the COVID-19 pandemic.

In the context of the coronavirus disease 2019 pandemic, we investigated the epidemiological and clinical characteristics of a young patient infected by avian influenza A (H5N6) virus in Anhui Province, East China, and analyzed genomic features of the pathogen in 2020. Through the cross-sectional investigation of external environment monitoring (December 29-31, 2020), 1909 samples were collected from Fuyang City. It was found that the positive rate of H5N6 was higher than other areas obviously in Tianma poultry market, where the case appeared. In addition, dual coinfections were detected with a 0.057% polymerase chain reaction positive rate the surveillance years. The virus was the clade 2.3.4.4, which was most likely formed by genetic reassortment between H5N6 and H9N2 viruses. This study found that the evolution rates of the hemagglutinin and neuraminidase genes of the virus were higher than those of common seasonal influenza viruses. The virus was still highly pathogenic to poultry and had a preference for avian receptor binding.

The Epidemiological Pattern and Co-infection of Influenza A and B by Surveillance Network From 2009 to 2014 in Anhui Province, China.

Influenza-like illness (ILI) is one of the most important public health problems globally, causing an enormous disease burden. Influenza infections are the most common cause of ILI. Bacterial and virus co-infection is common yet the data of co-infection with influenza A and B viruses are scarce. To identify the epidemiological patterns of and co-infection of influenza A and B in Anhui province, China, we analyzed the surveillance data of 5 years from 2009 to 2014 collected by the Chinese National influenzas network. The results showed that the weekly ratio of ILI was 3.96 ± 1.9% (95% CI 3.73-4.2%) in outpatients and the highest affected population was children under 5 years old. The epidemic of influenza viruses was highest during 2009-2010. For the other 4 surveillance years, school-aged people (5-14 years) were the most highly affected population. Influenza B and H3N2 viruses were more prevalent than H1N1pdm09 virus after 2010. In addition, a significant co-circulation of influenza A (H1N1pdm09 and H3N2) and influenza B virus was detected with 0.057% PCR positive rate during 2009-2014 in Eastern China, yet isolated only in pediatric patients. Our data reveals school-aged population would be the main vulnerable population and a distinct seasonality for influenza. In addition, the co-infection of influenza A and B were found in Anhui Province, China. Ongoing surveillance is critical to understand the seasonality variation and make evidence-based vaccination recommendations. Information on the epidemiological patterns and co-infections of influenza A and B can help us to implement different strategies for selecting vaccine formulations and monitoring new emerging influenza strains. In addition, the identification of the susceptible population can help us to develop more precise protection measures.