The Delta Variant poses a unique challenge to global health. We’ve compiled answers to some of the most common questions about Delta and other SARS-CoV-2 variants.
What is a variant?
A variant is a form of a virus that is genetically distinct from the original form.
“All organisms have mutation rates,” says Luis A Haddock, a graduate student at University of Wisconsin – Madison. “Unfortunately for us, viruses have one of the highest mutation rates of everything that currently exists. And even more unfortunately, RNA viruses have the highest mutation rates even among viruses.”
Luis works in the Friedrich Lab at UW-Madison, which has been sequencing SARS-CoV-2 genomes from positive test samples since the beginning of the pandemic. SARS-CoV-2 is constantly evolving, and sequencing can help us follow it through time and space. Most of the variants don’t behave any differently. A single nucleotide substitution might not even change the amino acid sequence of an encoded protein. However, occasionally a mutation will alter the structure or function of a protein.
The Brazilian state of Amazonas experienced two distinct waves of COVID-19 infections in 2020. After the first wave, a team from the University of Sao Paolo projected that the city of Manaus would reach the theoretical threshold for herd immunity by the end of the summer. However, a second COVID-19 wave erupted in December 2020, coinciding with the rise of Variant of Concern (VOC) P.1.
New research published in Nature Medicineexamined the different lineages of COVID-19 present in Brazil over time and determined that the two waves were driven by different variants. The first wave was driven by the variant B.1.195, which was imported from Europe in the spring. The second wave was largely driven by VOC P.1. The Nature Medicine study is the first to use viral sequences from samples collected throughout 2020 to explore the epidemiological and virological factors behind the two distinct COVID-19 waves.
Detecting VOC P.1 in Amazonas Samples
The researchers started by generating whole-genome sequences of 250 SARS-CoV-2 samples collected between March 2020 and January 2021. The survey showed that 20% of the sequences belonged to the B.1.195 lineage, and these mostly corresponded with the first exponential growth phase. 24% of the samples belonged to the P.1 lineage, and all of these samples corresponded with the rise of the second exponential growth phase. The largest share belonged to B.1.1.28 (37%), which replaced B.1.195 as the dominant variant in Brazil shortly after the first wave until the rise of VOC P.1.
The team also used real-time RT-PCR to analyze 1,232 positive samples collected in Amazonas between November 1, 2020 and January 21, 2021. The assay was designed to detect a deletion in NSP6, which is a signature mutation of VOC P.1. None of the samples collected before December 16 showed the NSP6 deletion, but it was common in samples starting in mid-December. Combining the two analysis methods, the team found the P.1 lineage in 0% of samples collected in November 2020, but by January 1-15 it was present in 73.8% of samples.
This data supports the theory that VOC P.1 first emerged in December 2020 and was the dominant lineage driving the second wave in Amazonas.
Two COVID-19 Waves: Virological and Epidemiological Factors
In addition to tracking the prevalence of lineages throughout the pandemic, the researchers also offered suggestions for how Amazonas experienced two distinct waves of COVID-19 infections.
Using computer modeling, the team found a significant reduction in reproductive efficiency (Re) of lineages B.1.195 and B.1.1.28 in April-May 2020, around the same time that Amazonas increased social distancing measures. Transmission rates remained low until the interventions were relaxed in September 2020. This suggests that the reduction in cases was not a result of herd immunity. Instead, nonpharmaceutical interventions (NPI) limited the first wave and contained the spread through the summer.
Using real-time RT-PCR, the researchers found that the viral load of P.1 infections was nearly ten times the viral load of non-P.1 infection. They also referenced other research that found that VOC P.1 has a stronger affinity for the human receptor ACE2 than B.1.195 and B.1.1.28. P.1 is clearly a highly transmissible VOC, and it evolved in an ideal environment for rapid spread. Amazonas had relaxed social distancing measures by late 2020, P.1 was able to quickly reach extremely high infection rates.
The study did not directly address theories that P.1 evades immunity developed from prior infections, but they concluded that a combination of epidemiological and virological factors allowed P.1 to drive a second wave of COVID-19 in Amazonas starting in December.
The paper includes a supplementary note suggesting that NPIs instituted in Manaus in January 2021 significantly reduced transmission rates of VOC P.1. The team ends the paper by reiterating the importance of adequate social distancing measures to limit the spread of COVID-19 and prevent the emergence of new Variants of Concern.
Inflammation, a process that was meant to defend our body from infection, has been found to contribute to a wide range of diseases, such as chronic inflammation, neurodegenerative disorders—and more recently, COVID-19. The development of new tools and methods to measure inflammation is crucial to help researchers understand these diseases.
Cytokines—small signaling molecules that regulate inflammation and immunity—have recently become the focus of inflammation research due to their role in causing severe COVID-19 symptoms. In these severe cases, the patient’s immune system responds to the infection with uncontrolled cytokine release and immune cell activation, called the “cytokine storm”. Although the cytokine storm can be treated using established drugs, more research is needed to understand what causes this severe immune response and why only some patients develop it.
Every time a genome is replicated, there’s a chance that an error will be introduced. This is true for all life forms. On a small scale, these mutations can lead to genetic diseases or cancers. On a much larger scale, random mutations are an important tool of evolution.
During the COVID-19 pandemic, the SARS-CoV-2 virus has picked up many mutations as it spread around the world. Most of these mutations have been inconsequential – the virus didn’t change in any significant way. Others have given rise to variants such as B.1.1.7 and B.1.351, which present complications for public health efforts. By studying the evolution of the virus, we can monitor how it’s spreading and predict the characteristics of variants as they are detected.
A year after COVID-19 was declared a pandemic, collaborative efforts among pharma/biotech and academic researchers have led to remarkable progress in vaccine development. These efforts include novel mRNA vaccine technology, as well as more conventional approaches using adenoviral vectors. While vaccine deployment understandably has captured the spotlight in the fight against COVID-19, there remains an urgent need to develop therapeutic agents directed against SARS-CoV-2.
In the March 12 issue of Science, an editorial by Dr. Francis Collins, director of the U.S. National Institutes of Health (NIH), examines lessons learned over the past 12 months (1). Collins points out that many clinical trials of potential therapeutics were not designed to suit a public health emergency. Some were poorly designed or underpowered, yet they received considerable publicity—as was the case with hydroxychloroquine. Collins advises developing antiviral agents targeted at all major known classes of pathogens, to head off the next potential pandemic before it becomes one. A news feature in the same issue discusses the current state of coronavirus drug development (2).
The present crop of drug candidates is remarkably diverse, including repurposed drugs that were originally developed to treat diseases quite different from COVID-19. Typically, however, the mainstream candidates belong to two broad classes: small-molecule antiviral agents and large-molecule monoclonal antibodies (mAbs).
Small- and medium-sized companies are critical to the Spanish economy. During 2020 the COVID-19 pandemic made business difficult for many of these companies, yet they have demonstrated strength and resourcefulness and have led the pandemic recovery in Spain in many ways. Recently, Promega Biotech Ibérica was recognized with a Madrid Community SME (small- and medium-sized business) Award along with 15 other companies. The awards were presented by Manuel Giménez, Minister of Economy, Employment and Competitiveness of the Madrid Region, Andres Navarro delegate director of La Razón, and Francisco Marhuenda, director of La Razón. As part of the award, Promega Biotech Ibérica General Manager, Gijs Jochems, was interviewed about the award and Promega’s work in the region.
According to Gijs Jochems, General Manager of Promega Biotech Ibérica, while Promega Corporation is an American multinational company, it remains privately held, which offers a great deal of flexibility to the subsidiaries to adapt to local needs. It also allows the company to place increased emphasis on employee well-being (critical during the pandemic), reinvest profits in research and development, and work to mitigate the impact of company activities on the environment. All these business practices reflect a long-term vision of sustainable business growth.
As the SARS-CoV-2 virus spread around the world in early 2020, many researchers shifted their focus to support the global endeavors to address the challenge. For two professors at the University of Wisconsin, their efforts started with animal models to study pathogenicity and grew into massive SARS-CoV-2 sequencing and COVID-19 testing projects.
“Being a scientist in this field gives a sense of purpose, but also a sense of obligation and responsibility,” says David O’Connor, PhD. “You always want to feel like you’re living up to that.”
A worldwide pandemic requires scientific research to understand the viral pathogen. The focused efforts of global scientists are even more necessary in the face of a novel coronavirus like SARS-CoV-2, the causative agent of COVID-19. However, because SARS-CoV-2 causes human disease, research efforts are restricted by the need for physical laboratories that are equipped to handle the required level of containment and personnel trained to handle pathogens in these facilities. But what if we could bypass the restrictive facility requirements by engineering a synthetic, replication-defective version of SARS-CoV-2 that more researchers could use to study the pandemic coronavirus, expanding the capacity to test and develop methods to attenuate its devastating effect on humans?
The challenge is to develop a derivative of SARS-CoV-2 that reflects how it behaves in the cell but is compromised such that it is unable to infect cells more than a single time. That is, the virus can get into a cell or be introduced into cells and replicate but is unable to produce infectious virus would offer a pathway to expand research capacity without the use of special laboratory facilities. This replication-defective SARS-CoV-2 could be created to encode as much or as little of the genome needed to examine its lifecycle without becoming a fully infectious virus. In fact, this replication-defective version of SARS-CoV-2 could include additional genetic elements that could be used to control its expression, track the virus in cells and measure the level of its replication. This task has been undertaken by Dr. Bill Sudgen’s group at the University of Wisconsin–Madison McArdle Laboratory for Cancer Research, explained by graduate student Rebecca Hutcheson during her presentation “Making the Virus Causing COVID-19 Safe for Research”.
The past year has been a challenge. Amidst the pandemic, we’re thankful for the tireless work of our dedicated employees. With their support, we have continuously stayed engaged and prepared during all stages of the COVID-19 pandemic so that we can serve our customers at the highest levels.
How We Got Here
The persistent work by our teams has made a great impact on the support we can provide for scientists and our community during the pandemic. From scaling up manufacturing to investing in new automation, every effort has helped.
Promega has a long history of manufacturing reagents, assays, and benchtop instruments for both researching and testing viruses. When the pandemic began in 2020, we responded quickly and efficiently to unprecedented demands. In the past year, we experienced an approximately 10-fold increase in demand for finished catalog and custom products for COVID-19 testing. In response to these demands, we increased production lines. One year ago, we ran one shift five days per week. Currently, we run three shifts seven days per week. This change has allowed 50 different Promega products to support SARS-CoV-2 testing globally in hospitals, clinical diagnostic laboratories, and molecular diagnostic manufacturers. Additionally, our clinical diagnostics materials make up about 2/3 of COVID-19 PCR tests on the global market today. Since January 2020, Promega has supplied enough reagents to enable testing an estimated 700 million samples for SARS-CoV-2 worldwide.
Developments and Advances
Promega products are used in viral and vaccine research. This year, our technologies have been leveraged for virtually every step of pandemic response from understanding SARS-CoV-2 to testing to research studies looking at vaccine response.
We are extremely grateful for our employees. In the past year, we hired over 100 people and still have positions open today. While welcoming newcomers, this challenging year also reinforced the importance of our collaborative culture. Relationships at Promega have been built over multiple years. The long history of our teams allows us to stay coordinated while prioritizing product distribution to customers across the globe. It also leads to effective communication with colleagues and vendors. Those leading our manufacturing operations team, for example, have an average tenure of 15 years. Their history in collaborating through challenging situations helps them quickly focus where needed most.
Our 600 on-site employees support product manufacturing, quality, and R&D. They do it all while remaining COVID-conscious by social distancing, wearing masks, working split shifts, and restricting movement between buildings. While we continue to practice physical safety precautions, we also prioritize our employees’ mental health and wellness. Promega provides a variety of wellness resources including phone and video mental health sessions, virtual fitness and nutrition classes, and stress and anxiety tools.
What’s to Come
While we acknowledge that the COVID-19 is not over, we are proud of the support we have been able to provide to customers working both on pandemic research and critical research not related to COVID-19. Our policies of long-term planning and investing in the future has allowed us to respond quickly and creatively and learn from the experience.
When the Spectrum Compact CE System launched in June 2020, all the instrument service engineers that are part of the Promega Global Service & Support (GSS) Team needed to be trained on using and fixing the instrument. This is a challenging endeavor in the best of times, but the COVID-19 pandemic made it even more difficult. Thanks to the work of some dedicated teams and individuals, Promega service engineers around the world were able to receive remote instrument training. But how do you teach someone to repair an instrument when you can’t be in the same room?
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