Antibody Testing Alone is Not the Key to Re-Opening Society
Immunity tests have too many unknowns right now to make them very useful in determining protective antibody status.
[Editor's Note: We asked experts from different specialties to weigh in on a timely Big Question: "How should immunity testing play a role in re-opening society?" Below, a virologist offers her perspective.]
With the advent of serology testing and increased emphasis on "re-opening" America, public health officials have begun considering whether or not people who have recovered from COVID-19 can safely re-enter the workplace.
"Immunity certificates cannot certify what is not known."
Conventional wisdom holds that people who have developed antibodies in response to infection with SARS-CoV-2, the coronavirus that causes COVID-19, are likely to be immune to reinfection.
For most acute viral infections, this is generally true. However, SARS-CoV-2 is a new pathogen, and there are currently many unanswered questions about immunity. Can recovered patients be reinfected or transmit the virus? Does symptom severity determine how protective responses will be after recovery? How long will protection last? Understanding these basic features is essential to phased re-opening of the government and economy for people who have recovered from COVID-19.
One mechanism that has been considered is issuing "immunity certificates" to individuals with antibodies against SARS-CoV-2. These certificates would verify that individuals have already recovered from COVID-19, and thus have antibodies in their blood that will protect them against reinfection, enabling them to safely return to work and participate in society. Although this sounds reasonable in theory, there are many practical reasons why this is not a wise policy decision to ease off restrictive stay-home orders and distancing practices.
Too Many Scientific Unknowns
Serology tests measure antibodies in the serum—the liquid component of blood, which is where the antibodies are located. In this case, serology tests measure antibodies that specifically bind to SARS-CoV-2 virus particles. Usually when a person is infected with a virus, they develop antibodies that can "recognize" that virus, so the presence of SARS-CoV-2 antibodies indicates that a person has been previously exposed to the virus. Broad serology testing is critical to knowing how many people have been infected with SARS-CoV-2, since testing capacity for the virus itself has been so low.
Tests for the virus measure amounts of SARS-CoV-2 RNA—the virus's genetic material—directly, and thus will not detect the virus once a person has recovered. Thus, the majority of people who were not severely ill and did not require hospitalization, or did not have direct contact with a confirmed case, will not test positive for the virus weeks after they have recovered and can only determine if they had COVID-19 by testing for antibodies.
In most cases, for most pathogens, antibodies are also neutralizing, meaning they bind to the virus and render it incapable of infecting cells, and this protects against future infections. Immunity certificates are based on the assumption that people with antibodies specific for SARS-CoV-2 will be protected against reinfection. The problem is that we've only known that SARS-CoV-2 existed for a little over four months. Although studies so far indicate that most (but not all) patients with confirmed COVID-19 cases develop antibodies, we don't know the extent to which antibodies are protective against reinfection, or how long that protection will last. Immunity certificates cannot certify what is not known.
The limited data so far is encouraging with regard to protective immunity. Most of the patient sera tested for antibodies show reasonable titers of IgG, the type of antibodies most likely to be neutralizing. Furthermore, studies have shown that these IgG antibodies are capable of neutralizing surrogate viruses as well as infectious SARS-CoV-2 in laboratory tests. In addition, rhesus monkeys that were experimentally infected with SARS-CoV-2 and allowed to recover were protected from reinfection after a subsequent experimental challenge. These data tentatively suggest that most people are likely to develop neutralizing IgG, and protective immunity, after being infected by SARS-CoV-2.
However, not all COVID-19 patients do produce high levels of antibodies specific for SARS-CoV-2. A small number of patients in one study had no detectable neutralizing IgG. There have also been reports of patients in South Korea testing PCR positive after a prior negative test, indicating reinfection or reactivation. These cases may be explained by the sensitivity of the PCR test, and no data have been produced to indicate that these cases are genuine reinfection or recurrence of viral infection.
Complicating matters further, not all serology tests measure antibody titers. Some rapid serology tests are designed to be binary—the test can either detect antibodies or not, but does not give information about the amount of antibodies circulating. Based on our current knowledge, we cannot be certain that merely having any level of detectable antibodies alone guarantees protection from reinfection, or from a subclinical reinfection that might not cause a second case of COVID-19, but could still result in transmission to others. These unknowns remain problematic even with tests that accurately detect the presence of antibodies—which is not a given today, as many of the newly available tests are reportedly unreliable.
A Logistical and Ethical Quagmire
While most people are eager to cast off the isolation of physical distancing and resume their normal lives, mere desire to return to normality is not an indicator of whether those antibodies actually work, and no certificate can confer immune protection. Furthermore, immunity certificates could lead to some complicated logistical and ethical issues. If antibodies do not guarantee protective immunity, certifying that they do could give antibody-positive people a false sense of security, causing them to relax infection control practices such as distancing and hand hygiene.
"We should not, however, place our faith in assumptions and make return to normality contingent on an arbitrary and uninformative piece of paper."
Certificates could be forged, putting susceptible people at higher exposure risk. It's not clear who would issue them, what they would entitle the bearer to do or not do, or how certification would be verified or enforced. There are many ways in which such certificates could be used as a pretext to discriminate against people based on health status, in addition to disability, race, and socioeconomic status. Tracking people based on immune status raises further concerns about privacy and civil rights.
Rather than issuing documents confirming immune status, we should instead "re-open" society cautiously, with widespread virus and serology testing to accurately identify and isolate infected cases rapidly, with immediate contact tracing to safely quarantine and monitor those at exposure risk. Broad serosurveillance must be coupled with functional assays for neutralization activity to begin assessing how protective antibodies might actually be against SARS-CoV-2 infection. To understand how long immunity lasts, we should study antibodies, as well as the functional capabilities of other components of the larger immune system, such as T cells, in recovered COVID-19 patients over time.
We should not, however, place our faith in assumptions and make return to normality contingent on an arbitrary and uninformative piece of paper. Re-opening society, the government, and the economy depends not only on accurately determining how many people have antibodies to SARS-CoV-2, but on a deeper understanding of how those antibodies work to provide protection.
Pregnant & Breastfeeding Women Who Get the COVID-19 Vaccine Are Protecting Their Infants, Research Suggests
Becky Cummings, who got vaccinated in December, snuggles her newborn, Clark, while he takes a nap.
Becky Cummings had multiple reasons to get vaccinated against COVID-19 while tending to her firstborn, Clark, who arrived in September 2020 at 27 weeks.
The 29-year-old intensive care unit nurse in Greensboro, North Carolina, had witnessed the devastation day in and day out as the virus took its toll on the young and old. But when she was offered the vaccine, she hesitated, skeptical of its rapid emergency use authorization.
Exclusion of pregnant and lactating mothers from clinical trials fueled her concerns. Ultimately, though, she concluded the benefits of vaccination outweighed the risks of contracting the potentially deadly virus.
"Long story short," Cummings says, in December "I got vaccinated to protect myself, my family, my patients, and the general public."
At the time, Cummings remained on the fence about breastfeeding, citing a lack of evidence to support its safety after vaccination, so she pumped and stashed breast milk in the freezer. Her son is adjusting to life as a preemie, requiring mother's milk to be thickened with formula, but she's becoming comfortable with the idea of breastfeeding as more research suggests it's safe.
"If I could pop him on the boob," she says, "I would do it in a heartbeat."
Now, a study recently published in the Journal of the American Medical Association found "robust secretion" of specific antibodies in the breast milk of mothers who received a COVID-19 vaccine, indicating a potentially protective effect against infection in their infants.
The presence of antibodies in the breast milk, detectable as early as two weeks after vaccination, lasted for six weeks after the second dose of the Pfizer-BioNTech vaccine.
"We believe antibody secretion into breast milk will persist for much longer than six weeks, but we first wanted to prove any secretion at all after vaccination," says Ilan Youngster, the study's corresponding author and head of pediatric infectious diseases at Shamir Medical Center in Zerifin, Israel.
That's why the research team performed a preliminary analysis at six weeks. "We are still collecting samples from participants and hope to soon be able to comment about the duration of secretion."
As with other respiratory illnesses, such as influenza and pertussis, secretion of antibodies in breast milk confers protection from infection in infants. The researchers expect a similar immune response from the COVID-19 vaccine and are expecting the findings to spur an increase in vaccine acceptance among pregnant and lactating women.
A COVID-19 outbreak struck three families the research team followed in the study, resulting in at least one non-breastfed sibling developing symptomatic infection; however, none of the breastfed babies became ill. "This is obviously not empirical proof," Youngster acknowledges, "but still a nice anecdote."
Leaps.org inquired whether infants who derive antibodies only through breast milk are likely to have a lower immunity than infants whose mothers were vaccinated while they were in utero. In other words, is maternal transmission of antibodies stronger during pregnancy than during breastfeeding, or about the same?
"This is a different kind of transmission," Youngster explains. "When a woman is infected or vaccinated during pregnancy, some antibodies will be transferred through the placenta to the baby's bloodstream and be present for several months." But in the nursing mother, that protection occurs through local action. "We always recommend breastfeeding whenever possible, and, in this case, it might have added benefits."
A study published online in March found COVID-19 vaccination provided pregnant and lactating women with robust immune responses comparable to those experienced by their nonpregnant counterparts. The study, appearing in the American Journal of Obstetrics and Gynecology, documented the presence of vaccine-generated antibodies in umbilical cord blood and breast milk after mothers had been vaccinated.
Natali Aziz, a maternal-fetal medicine specialist at Stanford University School of Medicine, notes that it's too early to draw firm conclusions about the reduction in COVID-19 infection rates among newborns of vaccinated mothers. Citing the two aforementioned research studies, she says it's biologically plausible that antibodies passed through the placenta and breast milk impart protective benefits. While thousands of pregnant and lactating women have been vaccinated against COVID-19, without incurring adverse outcomes, many are still wondering whether it's safe to breastfeed afterward.
It's important to bear in mind that pregnant women may develop more severe COVID-19 complications, which could lead to intubation or admittance to the intensive care unit. "We, in our practice, are supporting pregnant and breastfeeding patients to be vaccinated," says Aziz, who is also director of perinatal infectious diseases at Stanford Children's Health, which has been vaccinating new mothers and other hospitalized patients at discharge since late April.
Earlier in April, Huntington Hospital in Long Island, New York, began offering the COVID-19 vaccine to women after they gave birth. The hospital chose the one-shot Johnson & Johnson vaccine for postpartum patients, so they wouldn't need to return for a second shot while acclimating to life with a newborn, says Mitchell Kramer, chairman of obstetrics and gynecology.
The hospital suspended the program when the Food and Drug Administration and the Centers for Disease Control and Prevention paused use of the J&J vaccine starting April 13, while investigating several reports of dangerous blood clots and low platelet counts among more than 7 million people in the United States who had received that vaccine.
In lifting the pause April 23, the agencies announced the vaccine's fact sheets will bear a warning of the heightened risk for a rare but serious blood clot disorder among women under age 50. As a result, Kramer says, "we will likely not be using the J&J vaccine for our postpartum population."
So, would it make sense to vaccinate infants when one for them eventually becomes available, not just their mothers? "In general, most of the time, infants do not have as good of an immune response to vaccines," says Jonathan Temte, associate dean for public health and community engagement at the University of Wisconsin School of Medicine and Public Health in Madison.
"Many of our vaccines are held until children are six months of age. For example, the influenza vaccine starts at age six months, the measles vaccine typically starts one year of age, as do rubella and mumps. Immune response is typically not very good for viral illnesses in young infants under the age of six months."
So far, the FDA has granted emergency use authorization of the Pfizer-BioNTech vaccine for children as young as 16 years old. The agency is considering data from Pfizer to lower that age limit to 12. Studies are also underway in children under age 12. Meanwhile, data from Moderna on 12-to 17-year-olds and from Pfizer on 12- to 15-year-olds have not been made public. (Pfizer announced at the end of March that its vaccine is 100 percent effective in preventing COVID-19 in the latter age group, and FDA authorization for this population is expected soon.)
"There will be step-wise progression to younger children, with infants and toddlers being the last ones tested," says James Campbell, a pediatric infectious diseases physician and head of maternal and child clinical studies at the University of Maryland School of Medicine Center for Vaccine Development.
"Once the data are analyzed for safety, tolerability, optimal dose and regimen, and immune responses," he adds, "they could be authorized and recommended and made available to American children." The data on younger children are not expected until the end of this year, with regulatory authorization possible in early 2022.
For now, Vonnie Cesar, a family nurse practitioner in Smyrna, Georgia, is aiming to persuade expectant and new mothers to get vaccinated. She has observed that patients in metro Atlanta seem more inclined than their rural counterparts.
To quell some of their skepticism and fears, Cesar, who also teaches nursing students, conceived a visual way to demonstrate the novel mechanism behind the COVID-19 vaccine technology. Holding a palm-size physical therapy ball outfitted with clear-colored push pins, she simulates the spiked protein of the coronavirus. Slime slathered at the gaps permeates areas around the spikes—a process similar to how our antibodies build immunity to the virus.
These conversations often lead hesitant patients to discuss vaccination with their husbands or partners. "The majority of people I'm speaking with," she says, "are coming to the conclusion that this is the right thing for me, this is the common good, and they want to make sure that they're here for their children."
CORRECTION: An earlier version of this article mistakenly stated that the COVID-19 vaccines were granted emergency "approval." They have been granted emergency use authorization, not full FDA approval. We regret the error.
After a Diagnosis, Patients Are Finding Solace—and Empowerment—in a Sensitive Corner of Social Media
Katherine Leon and her dog enjoy nice weather in their backyard in Virginia. Leon went from feeling like she was "wandering in the woods" with doctors who hadn't experienced her spontaneous coronary artery dissection, or SCAD, to starting the world's largest registry for research on the condition.
When Kimberly Richardson of Chicago underwent chemotherapy in 2013 for ovarian cancer, her hip began to hurt. Her doctor assigned six months of physical therapy, but the pain persisted.
She took the mystery to Facebook, where she got 200 comments from cancer survivors all pointing to the same solution: Claritin. Two days after starting the antihistamine, her hip felt fine. Claritin, it turns out, reduces bone marrow swelling, a side effect of a stimulant given after chemo.
Richardson isn't alone in using social media for health. Thirty-six percent of adults with chronic diseases have benefited from health advice on the internet, or know others who have. The trend has likely accelerated during COVID-19. "With increases in anxiety and loneliness, patients find comfort in peer support," said Chris Renfro-Wallace, the chief operating officer of PatientsLikeMe, a popular online community.
Sites like PatientsLikeMe and several others are giving rise to a patient-centered view of healthcare, challenging the idea that MD stands for medical deity. They're engaging people in new ways, such as virtual clinical trials. But with misinformation spreading online about health issues, including COVID-19, there's also reason for caution.
Engaged by Design
Following her diagnosis at age 50, Richardson searched the Web. "All I saw were infographics saying in five years I'd be dead."
Eventually, she found her Facebook groups and a site called Inspire, where she met others with her rare granulosa cell tumor. "You get 15 minutes with your doctor, but on social media you can keep posting until you satisfy your question."
Virtual communities may be especially helpful for people with rarely diagnosed diseases, who wouldn't otherwise meet. When Katherine Leon of Virginia suffered chest pain after the birth of her second son, doctors said it was spontaneous coronary artery dissection, or SCAD, involving a torn artery. But she had no risk factors for heart disease. Feeling like she was "wandering in the woods" with doctors who hadn't experienced her situation, she searched online and stumbled on communities like Inspire with members who had. The experience led her to start her own Alliance and the world's largest registry for advancing research on SCAD.
"Inspire is really an extension of yourself," she said. If designed well, online sites can foster what psychologist Keith Sawyer called group mind, a dynamic where participants balance their own voices with listening to others, maximizing community engagement in health. To achieve it, participants must have what Sawyer called a "blending of egos," which may be fostered when sites let users post anonymously. They must also share goals and open communication. The latter priority has driven Brian Loew, Inspire's CEO, to safeguard the privacy of health information exchanged on the site, often asking himself, "Would I be okay if a family member had this experience?"
The vibe isn't so familial on some of Facebook's health-focused groups. There, people might sense marketers and insurers peering over their shoulders. In 2018, a researcher discovered that companies could exploit personal information on a private Facebook community for BRCA-positive women. Members of the group started a nonprofit, the Light Collective, to help peer-to-peer support platforms improve their transparency.
PatientsLikeMe and Inspire nurture the shared experience by hosting pages on scores of diseases, allowing people to better understand treatment options for multiple conditions—and find others facing the same set of issues. Four in ten American adults have more than one chronic disease.
Sawyer observed that groups are further engaged when there's a baseline of common knowledge. To that end, some platforms take care in structuring dialogues among members to promote high-quality information, stepping in to moderate when necessary. On Inspire, members get emails when others reply to their posts, instead of instant messaging. The communication lag allows staff to notice misinformation and correct it. Facebook conversations occur in real-time among many more people; "moderation is almost impossible," said Leon.
Even on PatientsLikeMe and Inspire, deciding which content to police can be tough, as variations across individuals may result in conflicting but equally valid posts. Leon's left main artery was 90 percent blocked, requiring open heart surgery, whereas others with SCAD have angina, warranting a different approach. "It's a real range of experience," she explained. "That's probably the biggest challenge: supporting everyone where they are."
Critically, these sites don't treat illnesses. "If a member asks a medical question, we typically tell them to go to their doctor," said Loew, the Inspire CEO.
Increasingly, it may be the other way around.
The Patient Will See You Now
"Some doctors embrace the idea of an educated patient," said Loew. "The more information, the better." Others, he said, aren't thrilled about patients learning on their own.
"Doctors were behind the eight ball," said Shikha Jain, an oncologist in Chicago. "We were encouraged for years to avoid social media due to patient privacy issues. There's been a drastic shift in the last few years."
Jain recently co-founded IMPACT, a grassroots organization that networks with healthcare workers across Illinois for greater awareness of health issues. She thinks doctors must meet patients where they are—increasingly, online—and learn about the various platforms where patients connect. Doctors can then suggest credible online sources for their patients' conditions. Learning about different sites takes time, Jain said, "but that's the nature of being a physician in this day and age."
At stake is the efficiency of doctor-patient interactions. "I like when patients bring in research," Jain said. "It opens up the dialogue and lets them inform the decision-making process." Richardson, the cancer survivor, agreed. "We shouldn't make the physician the villain in this conversation." Interviewed over Zoom, she was engaging but quick to challenge the assumptions behind some questions; her toughness was palpable, molded by years of fighting disease—and the healthcare system. Many doctors are forced by that system into faster office visits, she said. "If patients help their doctor get to the heart of the issue in a shorter time, now we're going down a narrower road of tests."
These conversations could be enhanced by PatientsLikeMe's Doctor Visit Guide. It uses algorithms to consolidate health data that members track on the site into a short report they can share with their physicians. "It gives the doctor a richer data set to really see how a person has been doing," said Renfro-Wallace.
Doctors aren't the only ones benefiting from these sites.
Who Profits?
A few platforms like Inspire make money by connecting their members to drug companies, so they can participate in the companies' clinical trials to test out new therapies. A cynic might say the sites are just fronts for promoting the pharmaceuticals.
The need is real, though, as many clinical trials suffer from low participation, and the experimental treatments can improve health. The key for Loew, Inspire's CEO, is being transparent about his revenue model. "When you sign up, we assume you didn't read the fine print [in the terms of agreement]." So, when Inspire tells members about openings in trials, it's a reminder the site works with pharma.
"When I was first on Inspire, all of that was invisible to me," said Leon. "It didn't dawn on me for years." Richardson believes many don't notice pharma's involvement because they're preoccupied by their medical issues.
One way Inspire builds trust is by partnering with patient advocacy groups, which tend to be nonprofit and science-oriented, said Craig Lipset, the former head of clinical innovation for Pfizer. When he developed a rare lung disease, he joined the board of a foundation that partners with Inspire's platform. The section dedicated to his disease is emblazoned with his foundation's logo and colors. Contrast that with other sites that build communities at the direct behest of drug companies, he said.
Insurance companies are also eyeing these communities. Last month, PatientsLikeMe raised $26 million in financing from investors including Optum Ventures, which belongs to the same health care company that owns a leading health insurance company, UnitedHealthcare. PatientsLikeMe is an independent company, though, and data is shared with UnitedHealth only if patients provide consent. The site is using the influx of resources to gamify improvements in health, resembling programs run by UnitedHealth that assign nutrition and fitness "missions," with apps for tracking progress. Soon, PatientsLikeMe will roll out a smarter data tracking system that gives members actionable insights and prompts them to take actions based on their conditions, as well as competitions to motivate healthier behaviors.
Such as a race to vaccinate, perhaps.
Dealing with Misinformation
An advantage of health-focused communities is the intimacy of their gatherings, compared to behemoths like Facebook. Loew, Inspire's head, is mindful of Dunbar's rule: humans can manage only about 150 friends. Inspire's social network mapping suggests many connections among members, but of different strength; Loew hopes to keep his site's familial ambiance even while expanding membership. Renfro-Wallace is exploring video and voice-only meetings to enrich the shared experiences on PatientsLikeMe, while respecting members' privacy.
But a main driver of growth and engagement online is appealing to emotion rather than reason; witness Facebook during the pandemic. "We know that misinformation and scary things spread far more rapidly than something positive," said Ann Lewandowski, the executive director of Wisconsin Immunization Neighborhood, a coalition of health providers and associations countering vaccine hesitancy across the state.
"Facebook's moderation mechanism is terrible," she said. Vaccine advocates in her region who try to flag misinformation on Facebook often have their content removed because the site's algorithm associates their posts with the distortions they're trying to warn people about.
In the realm of health, where accessing facts can mean life or death—and where ad-based revenue models conflict with privacy needs—there's probably a ceiling on how large social media sites should scale. Loew views Inspire as co-existing, not competing with Facebook.
Propagandists had months to perfect campaigns to dissuade people from mRNA vaccines. But even Lewandowski's doctor was misinformed about vaccine side effects for her condition, multiple sclerosis. She sees potential for health-focused sites to convene more virtual forums, in which patient advocacy groups educate doctors and patients on vaccine safety.
Inspire is raising awareness about COVID vaccines through a member survey with an interactive data visualization. Sampling thousands of members, the survey found vaccines are tolerated well among patients with cancer, autoimmune issues, and other serious conditions. Analytics for online groups are evolving quickly, said Lipset. "Think about the acceleration in research when you take the emerging capability for aggregating health data and mash it up with patients engaged in sharing."
Lipset recently co-founded the Decentralized Trials and Research Alliance to accelerate clinical trials and make them more accessible to patients—even from home, without risking the virus. Sites like PatientsLikeMe share this commitment, collaborating with Duke's ALS Clinic to let patients join a trial from home with just two clinic visits. Synthetic control groups were created by PatientsLikeMe's algorithms, eliminating the need for a placebo arm, enabling faster results.
As for Richardson, the ovarian cancer patient, being online has given her another type of access—to experts. She was diagnosed this year with breast cancer. "This time is totally different," she said. On Twitter, she's been direct messaging cancer researchers, whose replies have informed her disease-management strategy. When her oncologists prescribed 33 radiation treatments, she counter-proposed upping the dosage over fewer treatments. Her doctors agreed, cutting unnecessary trips from home. "I'm immuno-compromised," she said. "It's like Russian roulette. You're crossing your finger you won't get the virus."
After years of sticking up for her own health, Richardson is now positioned to look out for others. She collaborated with the University of Illinois Cancer Center on a training module that lets patients take control of their health. She's sharing it online, in a virtual community near you. "It helps you make intelligent decisions," she said. "When you speak your physician's language, it shifts the power in the room."