COVID-19: Cancer drug may quench inflammation in severely ill patients

An international clinical trial has been launched after a cancer drug that targets the root cause of extreme inflammation showed promise in a preliminary study.

In some people with mild or moderate COVID-19, the illness caused by the SARS-CoV-2 virus, their condition briefly improves, only to suddenly worsen.

These people may then develop severe breathing difficulties, known as acute respiratory distress syndrome.

Scientists speculate that even when the infection is being brought under control, the virus can trigger an excessive immune response, causing hyper-inflammation of the lungs and other organs.

This type of inflammatory response is thought to begin when receptors in immune cells called macrophages recognize the genetic material of viruses such as SARS-CoV-2. They respond by initiating a massive release of immune-signalling molecules called cytokines.

This “cytokine storm” appears to cause the hyper-inflammation that damages the lungs and other organs of critically ill patients. Currently, no proven treatment can prevent or reverse the damage.

In macrophages, an enzyme called Bruton tyrosine kinase (BTK) is responsible for initiating the cytokine storm.

A drug that inhibits the activity of BTK — called acalabrutinib — is already in use as a treatment for certain blood cancers.

Damping down inflammation

Researchers at the National Cancer Institute, in the United States, realized that because acalabrutinib inhibits BTK, it could potentially reduce inflammation in people with severe COVID-19.

To test the safety and efficacy of the drug in this context, they collaborated with scientists at the National Institute of Allergy and Infectious Diseases, the Walter Reed National Military Medical Center, and four other hospitals in the country.

The researchers have published the results of their trial in the journal Science Immunology.

For between 10 and 14 days, the team administered the drug to 19 people hospitalized for COVID-19. At the start of the study, 11 participants were breathing with the help of oxygen masks, and eight were on ventilators.

By the end of the follow-up period, eight of the 11 patients who had been receiving supplemental oxygen no longer needed help breathing and had been discharged from the hospital.

Of the eight patients on ventilators at the start of the treatment, four had been taken off the machines, or “extubated,” and two had been discharged. Two of the patients had died. 

The drug, however, appeared to cause no toxic side effects.

The researchers also monitored two markers of inflammation in the blood — levels of a cytokine called interleukin 6 (IL-6) and C-reactive protein (CRP).

Of the 11 patients on supplemental oxygen at the start of the study, CRP levels returned to normal in 10 and were decreasing in one. Of the five patients who also had their IL-6 levels measured, the levels of three had returned to normal, and the levels of two had fallen sharply.

The picture was more mixed among the patients on ventilators. Reductions were smaller overall, and in some of these patients, the levels fluctuated.

Source: MedicalNews Today

Best available evidence supports physical distancing and wearing face masks

A new study provides the best available evidence for key ways of reducing SARS-CoV-2 transmission.

A new meta-analysis, which brings together a significant amount of research on SARS-CoV-2 and related coronavirus protection, provides the best available evidence for physical distancing, mask use, and eye protection.

Until randomized controlled trials are conducted and can offer a greater degree of certainty, this study, which appears in The Lancet, provides doctors and policymakers with interim information on which to base key decisions.

Protective measures

The sudden, rapid emergence and spread of SARS-CoV-2 has left researchers searching for a safe, effective vaccine to reduce the transmission. However, the development of a vaccine may be 12–18 months away, if indeed such a vaccine can ever be found.

In the absence of a vaccine or other treatments that would slow the spread of the virus, public health organizations have recommended a series of social and behavioral changes to reduce the transmission.

In addition to frequent handwashing, authorities have emphasized the importance of physical distancing: leaving the house less frequently and maintaining as much distance as possible from others at all times while outside.

They also recommend the use of face masks and eye protection, particularly among healthcare workers and people working in the community.

However, experts are still debating when and how these policies should be implemented — including what constitutes the minimum distance that people should maintain from one another, when and where to wear personal protective equipment, and how effective this equipment is against the virus.

Significant meta-analysis

To address this, the World Health Organization (WHO) commissioned the present meta-analysis, which was conducted by an international team of researchers, clinicians, patients, and policy experts.

The authors sifted through over 20,000 research papers to find 44 comparative studies that related to the protective benefits of physical distancing, wearing face masks, and wearing eye protection.

The included studies addressed infection with the SARS-CoV-2 virus, the SARS virus, which caused an outbreak in the early 2000s, or the MERS-CoV virus, which caused an outbreak in the early 2010s. Because SARS-CoV and MERS-CoV are similar to SARS-CoV-2, research into these pathogens can provide insight.

The authors found no differences in the effectiveness of distancing, face masks, and eye protection in responses to the three coronaviruses and, therefore, feel confident in pooling the findings from the various studies.

Distancing and masks reduce transmission

The authors conclude that there is good evidence that maintaining a minimum distance of 1 meter, or about 3.3 feet, from other people is likely to have a significant effect on reducing the spread of the virus.

Across 38 studies that included information about distancing, infection rates overall were reduced to 2.6% when maintaining a distance of more than 1 meter from a person with the infection. By comparison, among studies in which distancing was less than 1 meter, the infection rate was 12.8%.

Furthermore, the authors found evidence that increasing the distance to 2 meters was likely to have an even greater effect.

Dr. Derek Chu, a lead author of the study, said: “We found that with each additional 1 meter of distance, the relative degree of protection increased about two-fold. […] Overall, [this] supports measures of at least 2 meters when feasible and possible.”

The authors point out that their finding of increased risk of infection at 2 meters has implications for the cut-off for contact tracing, and they suggest that 2 meters should be adopted universally.

The authors note that there is a consensus that the virus is transmitted through water droplets expelled from a person’s throat or nose when they cough or sneeze. These droplets are unable to stay airborne for very long, which is likely to explain why distances of at least 1 meter significantly reduce transmission.

Evidence of whether the virus can also transmit as an aerosol — surviving on very small particles that are also expelled as a person coughs and sneezes — has been mixed. These particles may be able to stay airborne for longer and thus infect a person at a greater distance.

As well as maintaining a minimum distance, face and eye masks are also designed to stop the spread of the virus, either by reducing the amount that a person expels or reducing the amount that can access a person’s mouth or eyes and, therefore, their respiratory system.

The authors found good evidence that both face masks and eye masks significantly reduced transmission of the virus for health care workers and people working in the community, such as care home workers.

The odds of developing an infection with a coronavirus were reduced by 78% when wearing any mask, compared with the odds of infection when not wearing a mask. When using masks that conform to the N95 standard, this figure increased to 96%.

According to co-lead study author Dr. Holger Schünemann, who, like Dr. Chu, works at McMaster University, in Ontario, Canada, “Although the direct evidence is limited, the use of masks in the community provides protection, and possibly N95 or similar respirators worn by healthcare workers suggest greater protection than other face masks.”

In a Lancet podcast, Dr. Schünemann confirmed that even wearing a “self-made face mask is better than having no face mask.”

While the study presents the best available evidence for policymakers to draw on when making key decisions about how to respond to the pandemic, particularly as lockdown measures begin to ease, the authors acknowledged their analysis has some limits.

None of the currently available studies looking at the protection afforded by physical distancing, face masks, and eye protection were randomized, and many of the studies did not specify exact distances.

Around three-quarters of the studies focused on healthcare settings, which means that while the evidence to support wearing face masks in these contexts is good, there is more uncertainty surrounding the use in nonhealthcare settings.

However, the authors state that once they had taken account of low levels of use of the highly effective N95 respirator masks in the community, they found other types of masks to be equally effective in both hospital and community settings.

Nonetheless, in the absence of randomized controlled trials that can provide more information and a greater degree of certainty — and until a vaccine or effective treatment is developed — the research presents policymakers and clinicians with valuable interim information on which to base key decisions.

MedicalNews Today

Older men less worried about COVID-19, study suggests

A study has found that older men may worry less about COVID-19 and may be less likely to make behavioral changes in response to the pandemic.

New research has found that despite being a more at-risk demographic, older men are likely to worry less and make fewer behavioral changes in response to the SARS-CoV-2 pandemic.

The research, published in The Journals of Gerontology, concludes that older men might require more education and intervention to ensure that they perceive the risks of COVID-19 accurately.

Worrying about COVID-19

The sudden emergence and rapid spread of the SARS-CoV-2 virus, as well as the risks associated with contracting COVID-19, have necessitated radical changes in people’s everyday life.

Emerging information about the virus has identified the demographics most vulnerable to a severe reaction to the virus.

While everyone should be making behavioral changes to reduce the spread of the virus, vulnerable groups need to take extra care, since severe COVID-19 can be life threatening.

According to the Centers for Disease Control and Prevention (CDC), 8 out of 10 COVID deaths in the United States have been people aged 65 and over. Research has also shown that men are at higher risk of a worse disease outcome, including death.

Given this, one may expect that men aged 65 and over may be more cautious and more worried about the virus. However, previous research has shown that older men are less likely to worry about death and their mortality than other demographics.

According to Dr. Sarah Barber, a gerontology and psychology researcher at Georgia State University and corresponding author of the study, “[n]ot only do older adults exhibit less negative emotions in their daily lives, they also exhibit less worry and fewer PTSD symptoms following natural disasters and terrorist attacks.

“In normal circumstances, not worrying as much is a good thing. Everyday life is probably happier if we worry less. However, where COVID-19 is concerned, we expected that lower amounts of worry would translate into fewer protective COVID-19 behavior changes.”

The present paper explored whether these known reductions in worry were the same or similar concerning COVID-19 and if this was likely to affect a person’s likelihood of making behavioral changes in response to the virus.

Risk, worry, and behavioral changes

To conduct the research, the authors gathered participants aged 18–35 and 65–81. After excluding participants who had received a diagnosis of COVID-19, the remaining sample consisted of 146 younger people (78 women, 68 men) and 156 older people (74 women, 82 men).

The researchers asked each participant to fill in a questionnaire to assess their relative levels of risk perception, worry, and behavior changes in response to the pandemic.

The researchers assessed the risk by asking if the participants thought people were over-reacting to the virus and if they thought the virus was no worse than seasonal flu. The participants answered the questions according to a scale of 1 (strongly disagree) to 7 (strongly agree).

To assess worry, the participants answered a series of questions about whether they worried about catching COVID-19 or its negative effects on their livelihood. The questionnaire asked the participants to select one of the following options to indicate their levels of worry: (a) not at all, (b) a little, (c) a moderate amount, (d) a lot, and (e) a great deal.

The questionnaire also posed a series of questions to assess behavioral changes. Questions included whether the participants were washing their hands more frequently, if they were wearing a hygiene mask more often, or if they had stopped shaking hands. For each question, participants could respond either (a) Yes, (b) I am considering it, but not yet doing it, and (c) No.

Less worry and fewer changes

The study found that most people were moderately concerned about the pandemic, and 80% of respondents had made behavioral changes in response to it.

However, the study also found that older men worried less than other participants about COVID-19 and made the fewest changes to their behavior.

Despite these findings, Dr. Barber does not believe the answer is to encourage older men to worry more. As she and co-author Hyunji Kim note, “[w]orry has been associated with increased risk for cardiovascular disease, with poorer physical health, and with greater declines in learning and memory over time.”

Dr. Barber thinks it would be better to ensure older men accurately understand the risks of COVID 19.

“Our study showed that for older men, accurate perception of risk worked as well as worry to predict preventive behaviors,” Dr. Barber said.

An accurate perception of risk may have improved since the researchers conducted the study. Dr. Barber notes that the study took place “right after the pandemic was declared, and we all hope that a more accurate perception of risk has evolved over the last 2 months.”

Nonetheless, the study’s findings indicate the importance of ensuring people, particularly older men, have an accurate perception of the risks of COVID-19.

Source: MedicalNews Today

COVID-19 patients experience neurological symptoms

Altered mental status and stroke are the most common neurological symptoms that hospitalized COVID-19 patients experience, according to a new study from Italy.

People with SARS-CoV-2, which is the virus that causes COVID-19, can experience a variety of symptoms.

According to the Centers for Disease Control and Prevention (CDC), these are usually physical symptoms, such as fever or chills, a cough, fatigue, and shortness of breath.

Among the warning signs that indicate that a person needs emergency medical care, the CDC list confusion and an inability to wake up or stay awake.

Although the neurological symptoms associated with COVID-19 have received much less attention than the physical symptoms, some studies suggest that they are common among people with severe forms of the illness.

A study in the BMJ, for example, found that among COVID-19 patients who died at a hospital in Wuhan, China, 22% had experienced a disorder of consciousness, compared with only 1% of those who recovered.

A preprint of another study of hospitalized patients in China found that overall, 25% had central nervous system symptoms or diseases. These included headaches, dizziness, impaired consciousness, uncoordinated muscle movements, seizures, and strokes.

These were more likely in those with severe disease. For example, 6% in the severe group had strokes, compared with 1% in the non-severe group.

In the first published study of its kind, researchers at the University of Cincinnati in Ohio and several Italian universities analyzed the findings of imaging investigations into hospitalized patients in Italy who experienced neurological symptoms with COVID-19.

The researchers have now published their results in the journal Radiology.

Second epicenter

After China, Italy became the second epicenter of the COVID-19 pandemic. Italy has now had more than 33,000 deaths.

The researchers analyzed the records of patients treated at the University of Brescia, the University of Eastern Piedmont in Novara, and the University of Sassari.

Out of 725 patients, 15% experienced neurological symptoms or disease. Of this 15%, 99% underwent a CT scan.

The most common neurological symptoms were “altered mental state,” which 59% of the patients experienced, and ischemic strokes, which 31% of the patients experienced.

“Altered mental status” encompasses a wide range of possible signs and symptoms, including confusion, delirium, and coma.

Among the less common neurological symptoms were headache (12%), seizures (9%), and dizziness (4%).

Imaging revealed acute abnormalities in 47% of the patients. Among the most common findings were ischemic strokes, and in 6% of the patients, there were signs of intracranial hemorrhage.

Early interventions

“These newly discovered patterns could help doctors better and sooner recognize associations with COVID-19 and possibly provide earlier interventions,” says lead study author Dr. Abdelkader Mahammedi, an assistant professor of radiology at the University of Cincinnati.

The study was unable to shed light on whether or not SARS-CoV-2 directly damages the central nervous system. It might be that neurological symptoms are a side effect of critical illness. Lack of oxygen in the brain, for example, can cause confusion or loss of consciousness.

In addition, of the 108 patients, 71% had one or more preexisting chronic conditions. These included hypertension, diabetes, coronary artery disease, and cerebrovascular disease.

In their paper, the researchers cite accumulating evidence to suggest that some people with severe COVID-19 experience a “cytokine storm,” in which the body produces an excess of pro-inflammatory molecules called cytokines. This can cause blood clots, which can, in turn, trigger ischemic strokes.

“This topic definitely needs more research,” says Dr. Mahammedi.

“Currently,” he adds, “we have a poor understanding of the neurological symptoms in COVID-19 patients, whether these are arising from critical illness or from direct central nervous system invasion of SARS-CoV-2. We hope further study on this subject will help in uncovering clues and providing better interventions for patients.”

Source: MedicalNews Today

Eyes could provide early warning of Alzheimer’s

Working with a mouse model of Alzheimer’s, scientists have developed an imaging technique for detecting changes in the texture of the retina that are associated with the disease. Early diagnosis of the condition could aid efforts to slow its progression.

More than 5 million people aged 65 or older in the United States are living with Alzheimer’s, according to the Alzheimer’s Association. Given the aging population, that number is expected to reach 13.8 million by 2050.

Early intervention with medications and mental exercises can, potentially, slow the development of the disease, but it can be difficult for doctors to make a definitive diagnosis.

There are no clear biological signs, or “biomarkers,” of Alzheimer’s. Instead, doctors rely on indications of cognitive decline and, sometimes, brain scans.

Now, biomedical engineers at Duke University, in Durham, NC, have hit upon a technique that combines two existing technologies to detect signs of the disease in the retina at the back of the eye.

So far, they have only tested this technique in a mouse model of Alzheimer’s. But if it can be shown to work in humans, it could lead to the development of a relatively cheap, compact, and easy to use screening device.

The research appears in the journal Scientific Reports.

Window into the brain

According to the researchers, the retina is effectively an extension of the central nervous system and was once considered a window into the brain.

Previous studies have revealed that thinning of the retina is an early sign of Alzheimer’s. However, regular aging and other diseases, such as Parkinson’s and glaucoma, also cause this thinning.

The technology used to measure the thickness of the retina, known as optical coherence tomography (OCT), is like the optical equivalent of ultrasound. It builds up a cross-sectional image of the retina by sending waves of light into the tissues and recording how long they take to come back.

However, OCT can give inconsistent results, due to differences among the machines and how they are operated.

To address the technology’s shortcomings, the Duke researchers combined OCT with an imaging technique called angle-resolved low-coherence interferometry (a/LCI), which analyzes how the retina scatters light to measure its morphology.

In a mouse model of Alzheimer’s, they discovered that the topmost layer of the retina is rougher and more disordered than in mice without the disease.

Other studies have found that the plaques that characterize Alzheimer’s in the brain are also present in this layer of the retina, which is called the nerve fiber layer.

These plaques may be one of the distinctive features that give the retina a rougher, more variable texture in Alzheimer’s.

Easy and cheap

“Our hope is that we can use this insight to create an easy and cheap screening device that wouldn’t only be available at your doctor’s office but at places like your local pharmacy, as well,” says Adam Wax, a professor of biomedical engineering at Duke and the senior author of the study, which was led by graduate student Ge Song.

“You can’t get textural and structural information about the retina with OCT alone,” explains Song. “You need both imaging modalities. That’s the key innovation.”

Prof. Wax and colleagues are now working to incorporate a/LCI technology in a low-cost OCT device that he is developing through a spinoff company called Lumedica.

Existing OCT devices are bulky, weighing more than 60 pounds, and cost more than $50,000. Prof. Wax says his design weighs only 4 pounds, is about the size of a lunchbox, and could retail for less than $15,000.

Before the technology can be rolled out in clinics, however, the researchers will need to demonstrate that their multimodal imaging device can reliably differentiate between indications of Alzheimer’s, other diseases that affect the retina, and regular aging.

Source: MedicalNews Today

Mouthwash may reduce spread of the new coronavirus

A recent scientific review speculates that mouthwash could inhibit the spread of SARS-CoV-2, the virus responsible for COVID-19.

A new research review suggests that publicly available mouthwashes could, in theory, inhibit SARS-CoV-2. The team behind the review call for further research to be done to confirm their speculative findings.

If clinical trials prove effective, the findings, published in the journal Function, may provide another way to reduce the spread of the disease until scientists can produce an effective, publicly available vaccine.

Since the sudden emergence and rapid spread of the SARS-CoV-2 virus, scientists and researchers have focussed on the development of a vaccine that could help protect people vulnerable to COVID-19.

However, scientists have estimated that an effective, publicly available vaccine could take at least 12–18 months to develop.

In the meantime, some scientists are focusing on ways to reduce the rate of infection to controllable levels that will not overwhelm hospital intensive care units.

Other scientists have investigated the development of effective treatments that may reduce the transmission rate of the virus.

One area of research involves disrupting the way the virus can take over a cell of a host as it replicates itself.

Disrupting the envelopes

SARS-CoV-2, like other coronaviruses, is an enveloped virus. This means that it creates an outer membrane by drawing on the cells of a host organism.

This membrane allows the virus to replicate effectively. If scientists can disrupt this envelope, then this might slow down the spread of the virus within an organism.

Using soap and water or disinfectant can disrupt a viral envelope and kill the virus. Research has shown that disinfectants can kill the SARS-CoV-2 virus.

This is why health authorities and organizations encourage people to wash their hands and surfaces with soap or alcohol-based products regularly.

The present review proposes that some publicly available mouthwashes may be able to help fulfill this role.

Scientists have shown that the virus replicates significantly in the throat. This may mean that a patient with COVID-19 is likely to have the highest concentration of the virus in this area. With high levels of the virus in the throat, it is easy for a person to transmit it through breathing, coughing, and sneezing.

Previous research into alcohol’s ability to disrupt the SARS-CoV-2 envelope has focused on products with a high alcohol content of between 60% and 70%.

This is because manufacturers typically design alcohol-based products to be effective in a variety of circumstances, including viruses, bacteria, and fungi.

However, there is little high-quality research exploring how lower-strength alcohol-based products might affect the viral envelope.

A significant spread from the throat

The authors of the current study wanted to see if alcohol-based mouthwashes — which come into contact with a person’s throat, a key site for viral load, and a source of viral transmission — could, in theory, inhibit the transmission of the virus or reduce its severity.

Put simply, if a significant spread of the virus originates from the throat, then it makes sense to trial the efficacy of products that have the potential to kill the virus at this location.

The authors note that due to the speed that the new coronavirus emerged, there is still much to learn about how it functions.

As such, their theory relies on certain assumptions that may turn out to be unfounded.

For example, scientists do not know how the virus moves from a person’s throat or nose to the lungs. The authors note that this could occur through breathing in dead viral cell debris, viral shedding, or neighboring cells becoming infected.

However, given the urgency of the public health crisis, it is necessary to propose speculative theories that scientists can then test in laboratories and, finally, in clinical trials.

Mouthwashes might be effective

Although there is little scientific literature exploring the effects of low-alcohol concentrations on viral envelopes, the authors drew on research that looked at the effects on mammalian cells.

The virus develops its envelope from these cells. So, it may be possible to compare the effects on these cells to the potential effects on the viral envelope.

After studying the literature, the researchers found that there was good reason to suppose that some low-alcohol products would, in theory, be able to disrupt the viral envelope of SARS-CoV-2.

The authors make it clear that their research is speculative. Researchers need to carry out more research to discover whether mouthwashes will affect the new coronavirus.

Nonetheless, this work shows that, in principle, this is a valuable area to study. This type of research is made urgent by the current global public health crisis.

Source: MedicalNews Today

Close relative of SARS-CoV-2 found in bats

Researchers have identified a new coronavirus that is closely related to SARS-CoV-2, the virus behind COVID-19. The discovery provides fresh evidence that SARS-CoV-2 evolved naturally and was not produced in a lab. The new virus is not likely to infect humans.

Since the start of the coronavirus pandemic, rumors have circulated that the SARS-CoV-2 virus, which causes COVID-19, emerged from a laboratory in Wuhan, the city in China where the outbreak began.

This theory was recently given credence by United States President Donald Trump, who claimed to have evidence that SARS-CoV-2 originated in a Chinese laboratory. However, he has not shared any information that would support this claim.

Meanwhile, a growing body of scientific research strongly indicates that SARS-CoV-2 was not manufactured.

New research published in the journal Current Biology adds to the evidence that the virus may have evolved naturally.

The team — led by researchers from Shandong First Medical University, in China — identified a new coronavirus in bats that is closely related to SARS-CoV-2. The two viruses are so closely related that it is highly unlikely that SARS-CoV-2 emerged from a laboratory.

The spike protein

Much of the debate about the origin of the novel coronavirus has centered on its spike protein, with which the virus binds to receptors on a host cell, ultimately allowing the virus to infect the cell and cause disease.

At the point where the two parts of the spike protein meet, there are an extra four amino acids, representing a difference from other coronaviruses. This feature, known as the S1/S2 insertion, is highly unusual and, so far, unique to SARS-CoV-2.

This unique characteristic of the spike protein has fuelled the idea that the virus may have been created in a laboratory.

“Since the discovery of SARS-CoV-2, there have been a number of unfounded suggestions that the virus has a laboratory origin. In particular, it has been proposed the S1/S2 insertion is highly unusual and perhaps indicative of laboratory manipulation,” elaborates senior author Prof. Weifeng Shi, director of the Institute of Pathogen Biology at the university.

A close relative

In order to compare the novel coronavirus to other, similar viruses, the researchers analyzed the genomes of 302 samples collected from 227 bats. The bats belonged to 20 different species.

The samples were collected from Yunnan province, in China, between May and October 2019 and sent for analysis in early January 2020, soon after SARS-CoV-2 was discovered.

Their genetic analysis identified a new coronavirus, called RmYN02, which has a very similar genome to SARS-CoV-2. The two viruses share 93.3% of their genetic information.

In some genetic regions, the new virus is even more similar than SARS-CoV-2’s current closest relative, RaTG13, which was also identified in bats from Yunnan.

In one of the longest parts of the genome that encodes for protein, RmYN02 shares 97.2% of its RNA with SARS-CoV-2.

Most importantly, according to the authors, RmYN02 has similar amino acid insertions in its spike protein, which suggests that these events — while highly unusual — occur naturally in evolution.

The evolutionary ancestry of SARS-CoV-2

Although the insertions found in the new virus are not exactly the same as those in SARS-CoV-2, the fact that such similar genetic events have occurred in both viruses strongly suggests that they can occur naturally.

The team is hopeful that further investigations will identify other related viruses, eventually helping to explain exactly how SARS-CoV-2 made its way to humans.

It is important to note that the newly identified virus is not likely to infect humans. This is because it does not contain the same receptor-binding domain as SARS-CoV-2, which helps the latter infect human cells.

Source: MedicalNews Today