BY NOW, many people know the story of the two Missouri hair stylists who saw 139 clients while they were developing symptoms of Covid-19 until they each tested positive for the virus. Yet not one of the 104 clients who agreed to be interviewed became infected. Both stylists and every client had worn some face covering.
Said CDC Director Robert Redfield , “If we could get everybody to wear a mask right now, I really think in the next four, six, eight weeks, we could bring this epidemic under control.”
Last week, along with viral transmission via infected persons and contaminated surfaces, the World Health Organization added airborne particles that “defy gravity—able to hang in the air for many hours or even days, and travel the length of a room,” according to Kobe University fluid dynamics expert Makoto Tsubokura.
The best defense against aerosolized virus particles: diffusing and diluting them by opening windows and doors, ensuring HVAC systems circulate fresh air, even using small desk fans—and always wearing a mask. Since February, the Japanese have kept Covid-19 numbers down by countering airborne particles and avoiding “the three Cs”: cramped spaces, crowded areas and close conversation.
For anyone needing extra motivation to take strict precautions, however, the more time that passes before becoming infected means better chances of recovery as treatments continue to improve.
Although statistics on deaths have many confounding variables—ages of patients, numbers getting tested—in one Milan hospital, among patients about the same average age, from March to May, the percent of Covid-19 patients who died dropped from 20% to 2%.
For treating Covid-19, the greatest challenge is the drastically different remedies that work at each stage of infection— but could prove deadly if mis-timed —from antivirals early on to steroids and other medications to counter later-stage immune system overreaction.
Early-stage virus treatments all await more research. As the virus enters alveolar cells in the lungs that transport oxygen to the blood, it turns the cells into viral copy machines and blocks normal cell operations.
Antivirals must target the point in the virus’s lifecycle when it reproduces—and kill the virus without harming the human cells where it has lodged. Another challenge is the constant mutation of this coronavirus, with myriad possibilities of developing resistance to drugs or vaccines.
The antiviral drug remdesivir interferes with the enzyme that allows the virus to reproduce—both reducing amount of virus in the body and improving the lung disease caused by the virus. Remdesivir in one study to date reduced the hospital stay for 1,000 Covid-19 patients to 11 days compared to 15 for those taking a placebo—but was less effective in sicker patients, including those on a ventilator.
In the later stages of Covid-19, cytokines signal the body’s immune system to send “repairing blood” to the infected cells. With overactive cytokines, however, the lung cells drown—even those not yet infected—blocking transportation of oxygen into the body. The result, ARDS (acute respiratory distress system), is the cause of death in most Covid-19 patients.
In addition, overactive cytokines make blood vessels more permeable to facilitate passage of immune cells from the blood to attack the virus. But too much permeability stimulates the clotting system to produce a proliferation of little blood clots throughout the body, with results that include stroke as well as heart or kidney failure.
Among other remedies, convalescent plasma and monoclonal antibodies each have the potential to combat the virus at various stages of the infection—as well as for prevention in healthy people—but production in sufficient quantities is tricky.
Convalescent plasma from recovered patients—used for more than 100 years to treat everything from measles to SARS —can block the virus from infecting cells. Currently limited to intravenous administration, plasma has proven safe in almost 30,000 hospitalized patients in the U.S.
But its effectiveness remains uncertain in the absence of research that includes a control population. In addition, plasma collection has many requirements: donors must have received a positive test result for the virus, have had no symptoms for 14 days, currently test negative, have high enough antibody levels in their plasma—and have a blood type compatible with the patient receiving the donation.
Monoclonal antibodies—biotechnology drugs that can block the virus—are increasingly the focus of attention for Solidarity, WHO’s program to coordinate coronavirus research in different European countries, as well as for Operation Warp Speed in the U.S. Again, the challenge might be producing sufficiently large quantities.
Finally, the best treatment for late stage Covid-19 may be steroids—in particular, dexamethasone. But the timing of steroids is a balancing act—not so early that they suppress the immune system while it is still needed to fight the virus, but not so late that over-reactivity has become a death sentence.
Dexamethasone reduced deaths by one-third in patients on a ventilator in the massive U.K. Recovery Program that has enrolled 12,000 patients in hundreds of participating hospitals.
Meanwhile, a word-of-mouth treatment that has proved helpful is “proning,” also called “tummy time,” which involves flipping Covid-19 patients onto their stomachs to give the lungs more room to fill with air—compared with the supine position where the position of organs against the lungs can make it harder to breathe.
For many patients, a combination of several therapies given at different times during treatment has helped with recovery—as has greater awareness of “silent hypoxia,” when the lung cells are becoming dysfunctional in the absence of other symptoms.
As wait times for test results increase with recent surges of Covid-19 cases in the U.S.—making it harder to know an individual’s current infection status—the need to observe strict social distancing becomes more important. In an effort to create more useful messaging, Marm Kilpatrick, infectious diseases researcher at the University of California Santa Cruz suggests: “Wear a mask. Meet Outside. Give Space.”
Well-Being Editor Mary Carpenter is on a mission to keep us updated on Covid-19. To read more of her posts, click here.