The 501Y.V2 variants of SARS-CoV-2 containing multiple mutations in spike are now dominant in South Africa and are rapidly spreading to other countries. Here, experiments with 18 pseudotyped viruses showed that the 501Y.V2 variants do not confer increased infectivity in multiple cell types except for murine ACE2-overexpressing cells, where a substantial increase in infectivity was observed. Notably, the susceptibility of the 501Y.V2 variants to 12 of 17 neutralizing monoclonal antibodies was substantially diminished, and the neutralization ability of the sera from convalescent patients and immunized mice was also reduced for these variants. The neutralization resistance was mainly caused by E484K and N501Y mutations in the receptor-binding domain of spike. The enhanced infectivity in murine ACE2-overexpressing cells suggests the possibility of spillover of the 501Y.V2 variants to mice. Moreover, the neutralization resistance we detected for the 501Y.V2 variants suggests the potential for compromised efficacy of monoclonal antibodies and vaccines.

A total of 807 entire VP1 sequences of Coxsackievirus A6 (CV-A6) from mainland of China from 1992 to 2015, including 520 in this study and 287 from the GenBank database, were analysed to provide a basic framework of molecular epidemiological characteristics of CV-A6 in China. Sixty-five VP1 sequences including 46 representative CV-A6 isolates from 807 Chinese strains and 19 international strains from GenBank were used for describing the genotypes and sub-genotypes. The results revealed that CV-A6 strains can be categorised into 4 genotypes designated as A, B, C, and D according to previous data and can be further subdivided into B1–B2, C1–C2, and D1–D3 sub-genotypes. D3 is the predominant sub-genotype that circulated in recent years in mainland of China and represents 734 of 807 Chinese isolates. Sixty-six strains belong to D2, whereas B1 and C1 comprise a single strain each, and five AFP strains formed B2. Sub-genotype D3 first circulated in 2008 and has become the predominant sub-genotype since 2009 and then reached a peak in 2013, while D2 was mostly undetectable in the past years. These data revealed different transmission stages of CV-A6 in mainland of China and that sub-genotype D3 may have stronger transmission ability.

Adenovirus is one of the most common causes of viral acute respiratory infections. To identify the types of human adenoviruses (HAdVs) causing respiratory illness in Beijing, a sentinel surveillance project on the viral aetiology of acute respiratory infection was initiated in 2011. Through the surveillance project, 4617 cases of respiratory infections were identified during 2011-2013. Throat swabs (pharynx and tonsil secretions) were collected from all the patients, and 15 different respiratory viruses were screened by multiplex one-step PCR method. 45 were identified as adenovirus-positive from sporadic and outbreak cases of respiratory infection by a multiplex one-step RT-PCR method, and a total of 21 adenovirus isolates were obtained. Five HAdV types among three species, including HAdV-3 (species HAdV-B), HAdV-4 (species HAdV-E), HAdV-7 (species HAdV-B), HAdV-55 (species HAdV-B), and an undefined HAdV type (species HAdV-C) were identified. The comparison results of the penton base, hexon, and fiber gene sequences of the Beijing HAdV-3, HAdV-4, HAdV-7, and HAdV-55 strains in this study and those from the GenBank database indicated significant spatial and temporal conservation and stability of sequences within the genome; however, the phylogenetic relationship indicated that both strain BJ04 and strain BJ09 isolated in 2012 and 2013, respectively, may have recombined between HAdV-1 genome and HAdV-2 genome within species HAdV-C, indicating intraspecies recombination. This study confirmed that at least 5 HAdV types including HAdV-3, HAdV-4, HAdV-7, HAdV-55 and an undefined HAdV type were co-circulating and were the causative agents of respiratory tract infections in recent years in Beijing. HAdV-3, HAdV-4, HAdV-7, and HAdV-55 showed the apparent stability of the genomes, while intraspecies recombination was identified in strain BJ04 and BJ09. The recombinants carrying penton base gene of HAdV-1 as well as hexon and fiber genes of HAdV-2 might be a novel type of HAdV worthy of further study.

With the implementation of mumps virus (MuV) vaccination in the expanded program on immunization (EPI) in mainland China since 2008, the incidence of mumps has decreased, and the natural epidemic pattern of mumps has slightly changed during 2013–2015. The two epidemic peaks (April-July and November-December) became less obvious than those observed from 2004 to 2012. Children and adolescents younger than 15, particularly in the five-to-nine-year-old age group, remain the target group and should be the focus of high-quality immunization activities in mainland China. However, it was also found that the incidence and reported cases of mumps decreased in each age group during 2013–2015, particularly in the five-to-nine-year-old and ten-to-fourteen-year-old age groups. The proportion of mumps cases among adults in some provinces also increased. Unlike the changes in the epidemiological characteristics of mumps affected by vaccination, the data of MuV virology surveillance indicated that most of the MuV transmission chains have not yet been effectively interrupted, and MuV remains a natural epidemic pattern in mainland China. In the MuV virology surveillance, 194 MuV strains during 2013–2015 were isolated from 10 of 31 provinces in mainland China. Based on the phylogenetic analysis of the small hydrophobic (SH) gene, both genotype F (99.0%) and G (1.0%) were identified, and genotype F was still the predominant genotype continuously circulating in mainland China. Representative genotype F and G strains isolated in China from 1995 to 2012 were selected for further analysis. The results indicated that there were multiple transmission chains within genotype F, with no obvious geographical or time differences. The high genetic diversity of genotype F strains could be a result of the continuous transmission and evolution of the MuV in mainland China. Genotype G was also detected in four provinces in mainland China. Because of the limited epidemiological data, it was uncertain whether the genotype G MuV strains found in 2011 and 2013 were imported from other countries. Therefore, combined high-quality epidemiological and virological surveillance is necessary for mumps control; it can also be used to observe the changes in epidemiological characteristics and viral transmission of mumps over time after mumps-containing vaccine (MuCV) implementation and to provide a comprehensive epidemiological and genetic baseline for mumps elimination in mainland China.