Baltimore, Maryland, USA, January 15, 2021: As hospitalization and mortality from COVID-19 continue to surge around the world, it will be imperative to quickly distribute the vaccines that are proven to at least show short-term protection and overall safety. Combining vaccine distribution to protective measures (mask, physical distancing and hand washing) and novel approaches to treatment, offers, for the first time since the beginning of this pandemic, valid hope in mitigating the virus outbreak and returning the world to normal life. Yet, there are hurdles and challenges to overcome, namely, the emergence of viral variants and the potential shortage of vaccine doses. In this context, experts of the Global Virus Network (GVN) are joining forces and expertise to address these points and offer solutions.
The rapid global spread of SARS-CoV-2 variants that have emerged from the UK and South Africa have brought great concern. Epidemiological and modeling studies have shown their increased transmissibility, yet, these studies also show that the new variants do not significantly affect disease severity and mortality. These variants contain several mutations. Importantly, the two variants contain the N501Y mutation in the spike protein that can increase binding affinity of the virus to its host receptor, ACE2. Moreover, the variant from South Africa shows the E484K mutation that might, at least theoretically, enable the virus to escape the host’s immune response.
GVN experts are studying how these mutations affect currently available vaccines, diagnostics and therapeutics. A recent study showed that the 501Y mutation did not drastically affect the activity of neutralizing antibodies in convalescent serum. The effect of the E484K mutation on immune evasion and reinfection is currently characterized by using convalescent sera. The front-runner vaccine companies, Pfizer/BioNTech and Moderna, have stated that their vaccines can be effective against these variants. Since the vaccines are designed to elicit robust levels of polyclonal neutralizing antibodies, these minor changes may not greatly reduce protective efficacy of vaccines. However, this needs to be evaluated by using live viruses of variants. Also, a most important question regarding current and future vaccines is their impact on cellular immunity — which should be key for controlling the emergence of such variants. For diagnostics, the mutations in the spike proteins might lead to a failure in RT-PCR assay, and thus, targeting the consensus sequences for primer design would be required.
The Vaccine Strategies
Other than the development of mutations, another challenge relates to the potential shortage of doses in the context of mass vaccination programs to curb the current pandemic. Since last December, several COVID-19 vaccines were granted emergency use authorization by regulators. These vaccines so far require two doses of vaccinations. Limited capacity by vaccine manufacturers are making it difficult to secure sufficient doses of vaccines to rapidly vaccinate as many people as possible and stop viral transmission. To boost their effort, the UK government has altered the vaccination regimen with the second dose of both vaccines being postponed to 12 weeks (as opposed to the recommend 21 and 28 days respectively) after the first dose. Other countries are also considering the same strategy.
GVN’s Collective Expert Opinion and Recommendations
GVN experts emphasize the need to urgently obtain data and evidence-based decisions on the strategy to extend the second dose timing to 12 weeks, or beyond what has already been tested in clinical trials. Indeed, GVN experts have several concerns about protective efficacy, vaccine safety and generation of new variants. Thus, GVN recommends additional and innovative studies to address several other possibilities for overcoming the shortage of vaccines and also to reinforce vaccine efficacy and duration of effect, such as using: (1) half the amount of vaccine for prime and boost vaccinations (2) heterologous prime and boost immunization by a combination of a COVID-19 vaccine and a non-specific effect of vaccine (i.e., BCG and oral poliovirus vaccine), and (3) heterologous prime and boost immunization by a combination of different COVID-19 vaccines (i.e., use of Pfizer/BioNTech and Oxford/AstraZeneca vaccines). GVN suggests launching well-designed clinical studies immediately so that the world can quickly learn which strategy is most effective. Experts in GVN Centers and Affiliates stand ready to collaborate and evaluate these vaccine strategies and extend their collective efforts to generate novel therapeutics.
About the Global Virus Network (GVN)
The Global Virus Network (GVN) is essential and critical in the preparedness, defense and first research response to emerging, existing and unidentified viruses that pose a clear and present threat to public health, working in close coordination with established national and international institutions. It is a coalition comprising eminent human and animal virologists from 61 Centers of Excellence and 11 Affiliates in 34 countries worldwide, working collaboratively to train the next generation of virologists, advance knowledge about how to identify and diagnose pandemic viruses, mitigate and control how such viruses spread and make us sick, as well as develop drugs, vaccines and treatments to combat them. No single institution in the world has expertise in all viral areas other than the GVN, which brings together the finest medical virologists to leverage their individual expertise and coalesce global teams of specialists on the scientific challenges, issues and problems posed by pandemic viruses. The GVN is a non-profit 501(c)(3) organization. For more information, please visit www.gvn.org. Follow us on Twitter @GlobalVirusNews