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One of many troubling complications of infection with SARS-CoV-2, the coronavirus that causes COVID-19, is its ability to trigger the formation of multiple blood clots, most often in older people but sometimes in younger ones, too. It raises the question of whether and when more aggressive blood thinning treatments might improve outcomes for people hospitalized for COVID-19.

The answer to this question is desperately needed to help guide clinical practice. So, I’m happy to report interim results of three large clinical trials spanning four continents and more than 300 hospitals that are beginning to provide critical evidence on this very question [1]. While it will take time to reach a solid consensus, the findings based on more than 1,000 moderately ill patients suggest that full doses of blood thinners are safe and can help to keep folks hospitalized with COVID-19 from becoming more severely ill and requiring some form of organ support.

The results that are in so far suggest that individuals hospitalized, but not severely ill, with COVID-19 who received a full intravenous dose of the common blood thinner heparin were less likely to need vital organ support, including mechanical ventilation, compared to those who received the lower “prophylactic” subcutaneous dose. It’s important to note that these findings are in contrast to results announced last month indicating that routine use of a full dose of blood thinner for patients already critically ill and in the ICU wasn’t beneficial and may even have been harmful in some cases [2]. This is a compelling example of how critical it is to stratify patients with different severity in clinical trials—what might help one subgroup might be of no benefit, or even harmful, in another.

More study is clearly needed to sort out all the details about when more aggressive blood thinning treatment is warranted. Trial investigators are now working to make the full results available to help inform a doctor’s decisions about how to best to treat their patients hospitalized with COVID-19. It’s worth noting that these trials are overseen by independent review boards, which routinely evaluate the data and are composed of experts in ethics, biostatistics, clinical trials, and blood clotting disorders.

These clinical trials were made possible in part by the Accelerating COVID-19 Therapeutic Interventions and Vaccines (ACTIV) public-private partnership and its ACTIV-4 Antithrombotics trials—along with similar initiatives in Canada, Australia, and the European Union. The ACTIV-4 trials are overseen by the NIH’s National Heart, Lung, and Blood institute and funded by Operation Warp Speed.

This ACTIV-4 trial is one of three Phase 3 clinical trials evaluating the safety and effectiveness of blood thinners for patients with COVID-19 [3]. Another ongoing trial is investigating whether blood thinners are beneficial for newly diagnosed COVID-19 patients who do not require hospitalization. There are also plans to explore the use of blood thinners for patients after they’ve been discharged from the hospital following a diagnosis of moderate to severe COVID-19 and to establish more precise methods for identifying which patients with COVID-19 are most at risk for developing life-threatening blood clots.

Meanwhile, research teams are exploring other potentially promising ways to repurpose existing therapeutics and improve COVID-19 outcomes. In fact, the very day that these latest findings on blood thinners were announced, another group at The Montreal Heart Institute, Canada, announced preliminary results of the international COLCORONA trial, testing the use of colchicine—an anti-inflammatory drug widely used to treat gout and other conditions—for patients diagnosed with COVID-19 [4].

Their early findings in treating patients just after a confirmed diagnosis of COVID-19 suggest that colchicine might reduce the risk of death or hospitalization compared to patients given a placebo. In the more than 4,100 individuals with a proven diagnosis of COVID-19, colchicine significantly reduced hospitalizations by 25 percent, the need for mechanical ventilation by 50 percent, and deaths by 44 percent. Still, the actual numbers of individuals represented by these percentages was small.

Time will tell whether and for which patients colchicine and blood thinners prove most useful in treating COVID-19. For those answers, we’ll have to await the analysis of more data. But the early findings on both treatment strategies come as a welcome reminder that we continue to make progress each day on such critical questions about which existing treatments can be put to work to improve outcomes for people with COVID-19. Together with our efforts to slow the spread of SARS-CoV-2, finding better ways to treat those who do get sick and prevent some of the worst outcomes will help us finally put this terrible pandemic behind us.

References:

[1] Full-dose blood thinners decreased need for life support and improved outcome in hospitalized COVID-19 patients. National Heart, Lung, and Blood Institute. January 22, 2021.

[2] NIH ACTIV trial of blood thinners pauses enrollment of critically ill COVID-19 patients. National Heart, Lung, and Blood Institute. December 22, 2020.

[3] NIH ACTIV initiative launches adaptive clinical trials of blood-clotting treatments for COVID-19. National Heart, Lung, and Blood Institute. September 10, 2020.

[4] Colchicine reduces the risk of COVID-19-related complications. The Montreal Heart Institute. January 22, 2021.

Links:

COVID-19 Research (NIH)

Combat COVID (U.S. Department of Health and Human Services, Washington, D.C.)

Accelerating COVID-19 Therapeutic Interventions and Vaccines (ACTIV) (NIH)

NIH Support: National Heart, Lung, and Blood Institute

It was an honor welcoming the 49th Vice President of the United States Kamala Harris to NIH on January 26, 2021. She received her second dose of the Moderna COVID-19 vaccine at the NIH Clinical Center in a livestreamed event. All was a thumbs up afterwards. The NIH community thanks Vice President Harris for her kind words and looks forward to her future visits to the NIH campus. Credit: NIH

Recently, there is a new and very hopeful COVID-19 number for everyone to track: the total number of vaccine doses that have been administered in the United States. If 80 percent of Americans roll up their sleeves in the coming months and accept COVID-19 vaccinations, we can greatly slow the spread of the novel coronavirus in our communities and bring this horrible pandemic to an end in 2021.

So far, more than 20 million people in our country have received one or two doses of either the Pfizer or Moderna vaccine. While this number is lower than initially projected for a variety of logistical reasons, we’re already seeing improvements in the distribution system that has made it possible to get close to 1 million doses administered per day.

If you want to keep track of the vaccine progress in your state over the coming weeks, it’s now pretty easy to do online. A fine resource is the vaccine information on the Centers for Disease Control and Prevention (CDC) COVID Data Tracker. It offers an interactive state-by-state map, as well as data on vaccinations in long-term care facilities. Keep in mind that there’s a delay of three to five days in reporting actual vaccinations from the states.

There’s also a lot of useful information on the Johns Hopkins Coronavirus Resource Center’s Vaccine Tracker. Posting the daily updates is a team, led by William Moss, that draws on the expertise of data scientists, analysts, programmers, and researchers. The Hopkins team gathers its vaccination data from each state’s official dashboard, webpages, press releases, or wherever cumulative numbers are reported. Not all states publish the same vaccine information, and that’s what can make the Vaccine Tracker so challenging to compile.

The Hopkins team now presents on its homepage the top 10 U. S. states and territories to vaccinate fully the highest percentage of their residents. With another click, there’s also a full rundown of vaccine administration by state and territory, plus the District of Columbia. The site also links to lots of other information about COVID-19—including cases, testing, contact tracing, and an interactive tool about vaccine development.

In uncertain times, knowledge can be a source of comfort. That’s what makes these interactive COVID-19 resources so helpful and empowering. They show that, with time, safe and effective COVID-19 vaccines will indeed coming to everyone. I hope that you will accept your vaccine, like I did when given the opportunity. However, until we get to the point where most Americans are immunized, we must stay vigilant and keep up our tried-and-true public health measures such as wearing masks, limiting physical interactions (especially indoors), and washing our hands.

Links:

COVID-19 Research (NIH)

CDC COVID Data Tracker (Centers for Disease Control and Prevention, Atlanta)

Coronavirus Resource Center (Johns Hopkins University School of Medicine)

William Moss (Johns Hopkins University, Baltimore)

International Vaccine Access Center (Johns Hopkins Bloomberg School of Public Health, Baltimore)

A new coronavirus vaccine approach works by attaching many spike protein receptor-binding domains (RBDs) to an engineered protein-based nanoparticle. In mice, the vaccine induced a cross-reactive antibody response capable of neutralizing many different coronavirus strains. Credit: Adapted from image by A. Cohen via BioRender

It’s truly encouraging to witness people all across our nation rolling up their sleeves to get their COVID-19 vaccines. That is our best chance to end this pandemic. But this is the third coronavirus to emerge and cause serious human illness in the last 20 years, and it’s probably not the last. So, this is also an opportunity to step up our efforts to develop vaccines to combat future strains of disease-causing coronavirus. With this in mind, I’m heartened by a new NIH-funded study showing the potential of a remarkably adaptable, nanoparticle-based approach to coronavirus vaccine development [1].

Both COVID-19 vaccines currently authorized for human use by the Food and Drug Administration (FDA) work by using mRNA to instruct our cells to make an essential portion of the spike protein of SARS-CoV-2, which is the novel coronavirus that causes COVID-19. As our immune system learns to recognize this protein fragment as foreign, it produces antibodies to attack SARS-CoV-2 and prevent COVID-19. What makes the new vaccine technology so powerful is that it raises the possibility of training the immune system to recognize not just one strain of coronavirus—but up to eight—with a single shot.

This approach has not yet been tested in people, but when a research team, led by Pamela Bjorkman, California Institute of Technology, Pasadena, injected this new type of vaccine into mice, it spurred the production of antibodies that react to a variety of different coronaviruses. In fact, some of the mouse antibodies proved to be reactive to related strains of coronavirus that weren’t even represented in the vaccine. These findings suggest that if presented with multiple different fragments of the spike protein’s receptor binding domain (RBD), which is what SARS-like coronaviruses use to infect human cells, the immune system may learn to recognize common features that might protect against as-yet unknown, newly emerging coronaviruses.

This new work, published in the journal Science, utilizes a technology called a mosaic nanoparticle vaccine platform [1]. Originally developed by collaborators at the University of Oxford, United Kingdom, the nanoparticle component of the platform is a “cage” made up of 60 identical proteins. Each of those proteins has a small protein tag that functions much like a piece of Velcro®. In their SARS-CoV-2 work, Bjorkman and her colleagues, including graduate student Alex A. Cohen, engineered multiple different fragments of the spike protein so each had its own Velcro-like tag. When mixed with the nanoparticle, the spike protein fragments stuck to the cage, resulting in a vaccine nanoparticle with spikes representing four to eight distinct coronavirus strains on its surface. In this instance, the researchers chose spike protein fragments from several different strains of SARS-CoV-2, as well as from other related bat coronaviruses thought to pose a threat to humans.

The researchers then injected the vaccine nanoparticles into mice and the results were encouraging. After inoculation, the mice began producing antibodies that could neutralize many different strains of coronavirus. In fact, while more study is needed to understand the mechanisms, the antibodies responded to coronavirus strains that weren’t even represented on the mosaic nanoparticle. Importantly, this broad antibody response came without apparent loss in the antibodies’ ability to respond to any one particular coronavirus strain.

The findings raise the exciting possibility that this new vaccine technology could provide protection against many coronavirus strains with a single shot. Of course, far more study is needed to explore how well such vaccines work to protect animals against infection, and whether they will prove to be safe and effective in people. There will also be significant challenges in scaling up manufacturing. Our goal is not to replace the mRNA COVID-19 vaccines that scientists developed at such a remarkable pace over the last year, but to provide much-needed vaccine strategies and tools to respond swiftly to the emerging coronavirus strains of the future.

As we double down on efforts to combat COVID-19, we must also come to grips with the fact that SARS-CoV-2 isn’t the first—and surely won’t be the last—novel coronavirus to cause disease in humans. With continued research and development of new technologies such as this one, the hope is that we will come out of this terrible pandemic better prepared for future infectious disease threats.

References:

[1] Mosaic RBD nanoparticles elicit neutralizing antibodies against SARS-CoV-2 and zoonotic coronaviruses. Cohen AA, Gnanapragasam PNP, Lee YE, Hoffman PR, Ou S, Kakutani LM, Keeffe JR, Barnes CO, Nussenzweig MC, Bjorkman PJ. Science. 2021 Jan 12.

Links:

COVID-19 Research (NIH)

Bjorkman Lab (California Institute of Technology, Pasadena)

NIH Support: National Institute of Allergy and Infectious Diseases