COVID-19

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Dr. Deborah Fuller, a professor of microbiology at the Washington University School of Medicine, in her lab.

© University of Washington. Used with Permission.

With several companies progressing through Phase III clinical trials, the much-awaited coronavirus vaccines may finally become reality within a few months.

But some scientists question whether these vaccines will produce a strong and long-lasting immunity, especially if they aren't efficient at mobilizing T-cells, the body's defense soldiers.

"When I look at those vaccines there are pitfalls in every one of them," says Deborah Fuller, professor of microbiology at the Washington University School of Medicine. "Some may induce only transient antibodies, some may not be very good at inducing T-cell responses, and others may not immunize the elderly very well."

Generally, vaccines work by introducing an antigen into the body—either a dead or attenuated pathogen that can't replicate, or parts of the pathogen or its proteins, which the body will recognize as foreign. The pathogens or its parts are usually discovered by cells that chew up the intruders and present them to the immune system fighters, B- and T-cells—like a trespasser's mug shot to the police. In response, B-cells make antibodies to neutralize the virus, and a specialized "crew" called memory B-cells will remember the antigen. Meanwhile, an army of various T-cells attacks the pathogens as well as the cells these pathogens already infected. Special helper T-cells help stimulate B-cells to secrete antibodies and activate cytotoxic T-cells that release chemicals called inflammatory cytokines that kill pathogens and cells they infected.


"Each of these components of the immune system are important and orchestrated to talk to each other," says professor Larry Corey, who studies vaccines and infectious disease at Fred Hutch, a non-profit scientific research organization. "They optimize the assault of the human immune system on the complexity of the viral, bacterial, fungal and parasitic infections that live on our planet, to which we get exposed."

Despite their variety, coronaviruses share certain common proteins and other structural elements, Fuller explains, which the immune system can be trained to identify.

The current frontrunner vaccines aim to train our body to generate a sufficient amount of antibodies to neutralize the virus by shutting off its spike proteins before it enters our cells and begins to replicate. But a truly robust vaccine should also engender a strong response from T-cells, Fuller believes.

"Everyone focuses on the antibodies which block the virus, but it's not always 100 percent effective," she explains. "For example, if there are not enough titers or the antibody starts to wane, and the virus does get into the cells, the cells will become infected. At that point, the body needs to mount a robust T-cytotoxic response. The T-cells should find and recognize cells infected with the virus and eliminate these cells, and the virus with them."

Some of the frontrunner vaccine makers including Moderna, AstraZeneca and CanSino reported that they observed T-cell responses in their trials. Another company, BioNTech, based in Germany, also reported that their vaccine produced T-cell responses.

Fuller and her team are working on their own version of a coronavirus vaccine. In their recent study, the team managed to trigger a strong antibody and T-cell response in mice and primates. Moreover, the aging animals also produced a robust response, which would be important for the human elderly population.

But Fuller's team wants to engage T-cells further. She wants to try training T-cells to recognize not only SARV-CoV-2, but a range of different coronaviruses. Wild hosts, such as bats, carry many different types of coronaviruses, which may spill over onto humans, just like SARS, MERS and SARV-CoV-2 have. There are also four coronaviruses already endemic to humans. Cryptically named 229E, NL63, OC43, and HKU1, they were identified in the 1960s. And while they cause common colds and aren't considered particularly dangerous, the next coronavirus that jumps species may prove deadlier than the previous ones.

Despite their variety, coronaviruses share certain common proteins and other structural elements, Fuller explains, which the immune system can be trained to identify. "T-cells can recognize these shared sequences across multiple different types of coronaviruses," she explains, "so we have this vision for a universal coronavirus vaccine."

Paul Offit at Children's Hospitals in Philadelphia, who specializes in infectious diseases and vaccines, thinks it's a far shot at the moment. "I don't see that as something that is likely to happen, certainly not very soon," he says, adding that a universal flu vaccine has been tried for decades but is not available yet. We still don't know how the current frontrunner vaccines will perform. And until we know how efficient they are, wearing masks and keeping social distance are still important, he notes.

Corey says that while the universal coronavirus vaccine is not impossible, it is certainly not an easy feat. "It is a reasonably scientific hypothesis," he says, but one big challenge is that there are still many unknown coronaviruses so anticipating their structural elements is difficult. The structure of new viruses, particularly the recombinant ones that leap from wild hosts and carry bits and pieces of animal and human genetic material, can be hard to predict. "So whether you can make a vaccine that has universal T-cells to every coronavirus is also difficult to predict," Corey says. But, he adds, "I'm not being negative. I'm just saying that it's a formidable task."

Fuller is certainly up to the task and thinks it's worth the effort. "T-cells can cross-recognize different viruses within the same family," she says, so increasing their abilities to home in on a broader range of coronaviruses would help prevent future pandemics. "If that works, you're just going to take one [vaccine] and you'll have lifetime immunity," she says. "Not just against this coronavirus, but any future pandemic by a coronavirus."

Lina Zeldovich
Lina Zeldovich has written about science, medicine and technology for Scientific American, Reader’s Digest, Mosaic Science and other publications. She’s an alumna of Columbia University School of Journalism and the author of the upcoming book, The Other Dark Matter: The Science and Business of Turning Waste into Wealth, from Chicago University Press. You can find her on http://linazeldovich.com/ and @linazeldovich.

Alma Mater, a beloved bronze mother figure on the campus of the University of Illinois, Champaign-Urbana, wears a mask to encourage students to do the same as they return for the fall semester. Students are also expected to take a COVID-19 test twice a week.

UNIVERSITY OF ILLINOIS/FRED ZWICKY

China, South Korea and other places controlled the SARS-CoV-2 epidemic with the early use of strict lockdown and aggressive electronic contact tracing, monitoring, and enforcement.

The tussles in America over voluntary social distancing and wearing a mask in public suggest that more stringent enforcement methods adopted elsewhere would not work here. But one American university has emerged as a model of tough love pandemic management.

While many universities have become hot spots of COVID-19 infections this fall when students returned to campus, the University of Illinois was an exception. It has gotten the virus under control, at least for the moment, at a rate that is far below the national average and with minimal social disruption. Can the program they implemented work in our broader society?

The Illinois model is a comprehensive one which, as elsewhere, includes masking and social distancing, but it also requires a twice-weekly saliva test for SARS-CoV-2. All students and employees are assigned test days when they swipe their ID card and spit in a plastic tube, which is collected hourly and taken to a campus lab.

There a simplified but highly sensitive PCR genetic test goes through many cycles of amplifying the viral RNA. "Tracking three different viral RNA [genes] gives us very high accuracy," explains Martin Burke, the professor who developed the system and is monitoring its implementation at the University of Illinois Urbana-Champaign. They immediately retest any positive sample to confirm the results, "So we think our false positive rate is extremely low. … The goal is to notify the positive person within 30 minutes of a positive test results becoming known."


Testing everyone so frequently, with a sensitive test that can quickly detect small amounts of the virus soon after infection, and isolating those who test positive before the virus can grow to volumes that make it very infectious helps the Illinois system break the chain of transmission.

"The testing we have done is not a silver bullet, it has to be done in combination with other mitigation measures. Our modeling shows that if you have masks, social distancing, and contact tracing you get a very dramatic, in fact synergistic effect with this combination,' says Burke. "So it really has to be a holistic approach with lots of community engagement in order to make this process successful."

The real teeth of enforcement are that people have to display their health status to gain access to campus facilities. A green check mark over their photo on a college ID phone app means they are good to go but a big red X means they are not current on their testing or have tested positive for the virus. Their ID is inactivated and they cannot enter campus facilities until they become compliant. Burke puts it bluntly; "We stop them from going where they want to go, a measure first used successfully with the pandemic in Wuhan, China.

He says they have learned from their experience and evolved their approach. "We never modeled for people who tested positive to ignore that result and go to or host parties, which could spread the infection." But several students did just that, and a few have been suspended for it.

So the university clamped down on enforcing isolation and now requires some higher risk persons to test three times a week to catch any infections earlier. Since more than 95 percent of new infections were among undergraduates, with no crossover from them to the local community, faculty, or graduate students, they have cut back testing of the latter two groups to just once a week.

About a thousand positive tests results have come back so far but no one has been hospitalized. Part of that likely is because the undergraduate population is largely young and healthy with few risk cofactors. But it may also be that with early identification and isolation, about five percent of dorm rooms have been set aside for that purpose, the person adopts healthier patterns of sleeping and eating that allows the immune system to better fight off the virus.

"But when you compare that to the being able to educate our students, perform research, keep our community thriving, our businesses open, if you add it all up, it's a tremendous return on investment."

The logistics are quite impressive for the campus that in ordinary times is home to more than 50,000 students; a lab capable of churning through 20,000 tests a day, with notification of results within hours, not days as is common elsewhere. And the results are equally impressive. The rate of positive test results blipped up to around 3 percent when undergraduates arrived back on campus but that has plummeted to 0.35 percent for the last seven-day period of testing, a tiny fraction of the rate for the nation as a whole. Much of it can be attributed to the closed environment with limited outside contact that might reintroduce the virus.

Still, even while the campus population has dropped by about a third, they are detecting about 250 new infections a week.

The threat of outside contact adding to the risk is why the university amended the undergraduate school calendar to close for Thanksgiving, hold final classes and exams for the semester online, and not return until February.

It doesn't come cheap. Burke estimates it cost $10 million to set up the program and about the same each semester to operate. "But when you compare that to the being able to educate our students, perform research, keep our community thriving, our businesses open, if you add it all up, it's a tremendous return on investment."

Burke acknowledges that they started with some significant advantages. The community is geographically isolated, an electronically linked ID system was already in place for students and employees, they have the ability to control much activity through access to buildings, and they can expel those who do not conform. He believes their system can translate to similar settings but admits, "A big city is very different from a university community." Still, he believes many of those lessons can be translated to different settings.

An alternative story

However, the situation is very different at the University of Colorado, where new infections have surged since undergraduates returned in late August. Administrators recently switched all classes to online only in an attempt to control the virus.

But that wasn't enough for state authorities who cracked down further, just yesterday declaring a two-week lockdown of all students aged 18 to 22, prohibiting gatherings of any size, indoors or out. Students must stay in their rooms except for essential activities, and if any symptoms develop, report for testing. Fraternities and sororities were targeted as past hot spots of infection.

The police will be actively enforcing the lockdown, and violators can face a penalty of up to 90 days in jail and a $1,000 fine.

Skepticism

Public health largely is based upon an appeal to self-interest and altruism, and voluntary compliance with official guidance. Harm reduction often comes into play when an ideal solution meets resistance and coercion plays only a limited role, as when a person with infectious tuberculosis is not compliant with treatment. Many question whether the medical threat of COVID-19 justifies such a sweeping restriction of individual rights of movement and association imposed on everyone simply because of their age and place of residence as is happening in Colorado.

State and federal courts have begun to strike down as an unconstitutional overreach some of the more restrictive decrees to stay at home or close businesses ordered by state and local officials. What was once tolerated as a few weeks or even a few months of restrictions now seems to stretch without an end in sight, and threatens peoples' livelihoods. In this litigious country it seems only a matter of time before someone will challenge some aspects of the Illinois model or similar programs being set up elsewhere as an infringement of their rights.

"I have real concerns about what we have seen over the course of the past several months in terms of going from not enough testing being available to now having more testing [available] because people don't want to be tested, even when they have symptoms," says Michael Osterholm, a noted expert on pandemic preparedness at the University of Minnesota. "We have some college campuses reporting over fifty percent of the students refusing to be tested or refusing to give any of the contacts that might be followed up on."

Often those who have tested positive for the virus "don't want people to know that they're the potential reason there could be an outbreak in their small social circle," says LaQuandra Nesbitt, public health director for Washington, DC. Stigma is one of the main reasons why only 37% of newly infected people have provided names for contact tracing in D.C., and few offer more than a single name.

"We can't test every single person every single day, we would completely go broke, we would be looking at no other health problems. We're not the NFL," says Monica Gandhi. She is a professor of medicine at the University of California San Francisco and works closely with local health officials. "Just because we have a technology doesn't mean that we have to apply it for every purpose that may be indicated. … We would never dream of mass screening the public for influenza."

"Tests don't solve the problem," she argues. Masking is the most crucial piece for Gandhi, along with social distancing, washing hands regularly, and quarantine when testing positive or in contact with someone who is. Those are the actions that break the ongoing spread of transmission. She does support regular testing in high-risk settings such as nursing homes, inpatients in hospitals, and prisons, and periodic surveys in the general population to better understand where the virus is moving.

Drawing from experience with HIV, Gandhi worries that the stigma of a positive result will drive people away from testing. "Low-income persons will be particularly hesitant to get tested, or to share contact information if they do test positive, if they think they may have to quarantine, not work or gain income." That is why San Francisco initially assisted people in isolation with payment of $1285 for two weeks of isolation and other support as part of a right to health program. And this fall, the State of California passed legislation requiring that large businesses continue to pay employees in quarantine.

Tools for self-protection

The American temperament, decentralization, size, administrative complexity, and sheer cost make it highly unlikely that a coercive one-size-fits-all Illinois approach will ever be rolled out from a university campus to the entire nation. People make different decisions in trading off between safety and personal freedom or autonomy, and many are likely to embrace a rapid, inexpensive self-test if one becomes available, much like a home pregnancy test, to proactively monitor their own health.

OraSure Technologies pioneered the first home test for HIV. It is the only over-the-counter saliva test for HIV approved for sale in the U.S. Results show in about 20 minutes. The company went on to develop versions of this test for hepatitis C and Ebola. Thus it came as no surprise when in April the Department of Health and Human Services awarded it a $710 thousand contract to develop a rapid antigen home test for SARS-CoV-2.

Initial optimization studies for the antigen test showed that a nasal sample rather than an oral one generated better results, OraSure president and CEO Stephen Tang told LeapsMag. A test using a nasal swab is expected to be available later this year while work continues to develop an antibody test that uses saliva. He says, "the fundamental challenge is not only to develop the tests but to get it to scale quickly. That's the only way it's really going to matter." The company has manufacturing capacity to produce 35 million tests a year, with about half for SARS-CoV-2, and will double that capacity in steps within the next twelve months, with all of the increased capacity dedicated to COVID-19.

Initial use will be limited to health care workers and by prescription, but the company hopes to make it available over the counter soon after the FDA finalizes its rules on these types of tests for COVID-19. Importantly, OraSure believes its nasal swab test will be able to meet the current FDA standards for at-home tests. No such tests have yet been approved.

Tang says they envision using a phone app with the test, but that's tied to "the question of our century; who owns the data? If you are an individual buying the test, are you really compelled to report to anybody? If you are an employer and you buy the test and your employees take it, are you then entitled to the information because you're the one administering the test? That's all still being debated as well" by regulators, lawyers, and ethicists.

The price hasn't been set but Tang notes that they have "vast experience" in selling directly to the consumer, physicians, and public health systems in the U.S. and in lower-income companies. "We are very aware of what the economics are and what the need is today. We're trying to make this product as widely available to as many people as possible."

Another tool that may help protect the self-motivated are cell phone apps that alert you to potential exposure to others with the virus. Apple, Google and others have developed versions of the app that all work on the same principle and, miraculously, are compatible between the Apple and Android operating system universes. At first glance they look promising.

The glitch is that where they have been available the longest, only about 15-20 percent of users bother to download it, says Bennett Cyphers, a staff technologist with the Electronic Freedom Foundation (EFF), a nonprofit that advocates for privacy and other concerns in cyberspace. He explains, "If 1 in 10 people have the app installed, then only 1 in 100 interactions between everyone is going to be captured by the app. It scales that way; the fewer people you have, then a really, really small fraction of contacts are actually detected."

It is important to remember that much of public health is not the result of policy but of what people do in their daily lives.

Importantly, about 20 percent of Americans do not own a smart phone with the capacity to handle the app; that percentage is even higher among lower income, less educated, older folks who often are most at risk for suffering a severe case of COVID-19. So the value of this tool is likely to remain largely theoretical.

Divining the future

"It's tough to make predictions, especially about the future," the great baseball sage Yogi Berra is reported to have said. Will the COVID-19 pandemic in the U.S. follow the path of Illinois or Colorado?

The recent past often is no guide to such predictions. France, Spain, and Israel once earned plaudits for early and strict enforcement of lockdowns to control spread of the virus and then eased up on those restrictions. At the same time the world watched with condemnation and fascination as Sweden chose to follow a more laissez faire approach, urging voluntary distancing and masking but no major curtailing of activity.

Today the rates of new infections of COVID-19 in the first three countries have exploded to equal or multiples of the rate in Sweden. Which approach was the correct policy? Most people say it is still too early to tell for sure. The same can be said for the examples of Illinois and Colorado.

And then there is the puzzling example of Manaus, the Brazilian city of 1.8 million in the middle of the Amazon which was slammed with infections as hard as New York City; without the medical infrastructure to cope with the virus, 4000 have died. But then, suddenly, new infections began to taper off, and nobody claims to understand why, it certainly wasn't because official policies changed. One guess is that perhaps the region reached herd immunity, but that is simply speculation.

One can pick and choose examples of tough enforcement of quarantine or none to prove their point for the short term. But draconian measures will not be tolerated for long in a free society, and there is no clear, overwhelming evidence that over the long run one policy approach works better than another.

It is important to remember that much of public health is not the result of policy but of what people do in their daily lives. We have come remarkably far in what is still only months since we first heard the name of the virus. Death rates have fallen dramatically as we have learned how to better manage severe disease, often by adapting treatments for other diseases. And there is reason for optimism with the large number of vaccine candidates already in human trials.

We also have learned that we can control much of our own fate through simple but concerted actions in our daily lives such as social distancing, wearing masks, and washing hands. Let's not only remember those facts, but practice them.

Bob Roehr
Bob Roehr is a biomedical journalist based in Washington, DC. Over the last twenty-five years he has written extensively for The BMJ, Scientific American, PNAS, Proto, and myriad other publications. He is primarily interested in HIV, infectious disease, immunology, and how growing knowledge of the microbiome is changing our understanding of health and disease. He is working on a book about the ways the body can at least partially control HIV and how that has influenced (or not) the search for a treatment and cure.