New vaccines, therapeutics and immunity elicited by natural infection create evolutionary pressure on SARS-CoV-2 to evolve and adapt to evade vaccine-induced and infection-elicited immunity. Vaccine and therapeutics developers thus find themselves in an “arms race” with the virus. The ongoing assessment of emerging SARS-CoV-2 variants remains essential as the global community transitions from an emergency response to a long-term management plan. Here, we describe how an authentic virus neutralisation assay using low passage clinical virus isolates has been employed to monitor resistance of emerging virus variants to neutralising antibodies from humans and experimentally infected hamsters. Sera and plasma from people who received three doses of a vaccine as well as those who received a bivalent booster were assessed against SARS-CoV-2 variants, up to and including JN.1. Contemporary or recent virus variants showed substantial resistance to neutralisation by antibodies from those who had received three doses of an ancestral vaccine but were still effectively neutralised by antibodies from individuals who had received a bivalent booster (ancestral/BA.1). In our recent studies, however, the JN.1 VOI was found to be significantly more resistant to neutralisation by antibodies from those who had received the ancestral/BA.1 bivalent boost. Convalescent sera from hamsters that had been experimentally infected with one of seven virus variants (ancestral, BA.1, BA.4, BA.5.2.1, XBB.1.5, XBB.1.16, XBB.2.3) were also tested here. The recent contemporary variant, BA.2.86, was effectively neutralised by sera from hamsters infected with XBB.1.5 and XBB.1.16 but it was not neutralised by sera from those infected with BA.5.2.1. These data support the recommendations given by the WHO that a new vaccine was required and should consist of an XBB sub-lineage antigen.

Despite a global effort, HIV remains a major public health burden with an estimated 1.5 million new infections occurring in 2020. HIV DNA is an important viral marker, and its monitoring plays a critical role in the fight against HIV: supporting diagnosis in infants and underpinning clinical management of patients under therapy.

In the summer of 2020, it became clear that the genetic composition of SARS-CoV-2 was changing rapidly. This was highlighted by the rapid emergence of the D614G mutation at that time. In the autumn of 2020, the project entitled “Agility” was initiated with funding from the Coalition for Epidemic Preparedness Innovations (CEPI) to assess new variants of SARS-CoV-2. The project was designed to reach out and intercept swabs containing live variant viruses in order to generate highly characterised master and working stocks, and to assess the biological consequences of the rapid genetic changes using both in vitro and in vivo approaches. Since November 2020, a total of 21 variants have been acquired and tested against either a panel of convalescent sera from early in the pandemic, and/or a panel of plasma from triple-vaccinated participants. A pattern of continuous evolution of SARS-CoV-2 has been revealed. Sequential characterisation of the most globally significant variants available to us, generated in real-time, indicated that the most recent Omicron variants appear to have evolved in a manner that avoids immunological recognition by convalescent plasma from the era of the ancestral virus when analysed in an authentic virus neutralisation assay.

Background: In HIV-1-exposed infants, nucleic acid testing (NAT) is required to diagnose infection since passively transferred maternal antibodies preclude antibody testing. The sensitivity of clinical NAT assays is lowered with infant antiretroviral prophylaxis and, with empiric very early antiretroviral treatment of high-risk infants, thereby impacting early infant diagnosis. Similarly, adult HIV-1 infections acquired under pre-exposure prophylaxis may occur at low levels (occult infection), with undetectable plasma viremia and indeterminate antibody tests, for which HIV-1 DNA testing maybe a useful adjunct. Cell-associated HIV-1 DNA concentrations are also used to monitor HIV-1 persistence in viral reservoirs with relevance to HIV-1 cure therapeutics, particularly in perinatal infections. Methods: The analytical sensitivity and specificity of an HIV-1 DNA droplet digital PCR (ddPCR) assay was determined, across different HIV-1 subtypes, using serial dilutions of a plasmid containing a 160-base pair sequence of the HIV-1 LTR-gag spiked into peripheral blood mononuclear cells (PBMCs), with MOLT-4 cells or PBMCs infected with different HIV-1 subtypes (A, B and C), and U1 cells spiked into PBMCs. Inter- and intra-run variability were used to determine assay precision. Results: The HIV-1 LTR-gag ddPCR assay was reliable and reproducible, and exhibited high analytical specificity with sensitivity to near single copy level, across multiple HIV-1 subtypes, and a limit of detection of 4.09 copies/million PBMCs. Conclusions: This assay has applications for detecting occult HIV-1-infection that may occur in the setting of combination and long-acting regimens used for HIV-1 prevention, across different HIV-1 subtypes, in both infants and adults, and in HIV-1 cure interventions, particularly with perinatal infections.

The increasing health threat arising from emerging infectious disease requires an urgent global response. The accelerated development of vaccines, diagnostics and treatments requires facilitated access to and timely transfer of pertinent research reagents between scientists, especially those from low- and middle-income countries (LMICs) which are frequently the worst affected. To meet this global need, we propose to establish a Centre for Emerging Disease Research Reagents (CEDRR) which will support research on those emerging diseases that pose the greatest threat. This initiative will be based on the model of the Centre for AIDS Reagents, a not-for-profit repository based at the National Institute for Biological Standards and Control (NIBSC), UK, which has been providing a sustained HIV research reagent resource to scientists worldwide for 30 years. CEDRR will encourage leading scientists to donate research materials under an established transfer agreement, that will enable onward supply of samples to requesting laboratories in a manner that protects intellectual property. In addition, we will prepare and commission novel research materials including non-infectious subgenomic clones, recombinant proteins, peptides and antibodies. All the reagents will be characterized and provided individually or as all-in-one packages for specific assays along with detailed data sheets and corresponding standard operating procedures. They will be available globally and access will be prioritized with the objective to help build research capacity in LMICs. In order to provide a service that will meet the scientific community need, CEDRR will actively participate in existing networks and consortia on emerging pathogens, provide frequent newsletters and held regular meetings to discuss reagent requirements. By building an infrastructure that will provide quality research reagents to scientists worldwide, CEDRR hopes to speed up the development of much needed vaccines, diagnostics and treatments to fight emerging pathogens.