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.
Friday Five: These boots were made for walking, even for people who can't
New boots could have you moving like Iron Man, based on research this month by Stanford scientists.
The Friday Five covers important stories in health and science research that you may have missed - usually over the previous week but, today, we're doing a lookback on breakthrough research over the month of October. There are plenty of controversies and troubling ethical issues in science – and we get into many of them in our online magazine – but this news roundup focuses on scientific creativity and progress to give you a therapeutic dose of inspiration headed into the weekend.
Listen on Apple | Listen on Spotify | Listen on Stitcher | Listen on Amazon | Listen on Google
This Friday Five episode covers the following studies published and announced over the past month:
- New boots could have you moving like Iron Man
- The problem with bedtime munching
- The perfect recipe for tiny brains
- The best sports for kids to avoid lifelong health risks
- Can virtual reality reduce pain?
Should egg and sperm donors reveal their identities? The debate pivots on genetics and medical history.
Cassandra Adams performs on stage at the Jersey City Theater Center in March 2019 to raise awareness about traumatic experiences that she and others have had with anonymous donor conception.
Until age 35, Cassandra Adams assumed her mother and father were her biological parents. Then she took saliva tests through two genealogy databases—23andMe and AncestryDNA—and discovered a discrepancy in her heritage. In bringing up the matter with her parents, she learned that fertility issues had led the couple to use a sperm donor.
“Most people my age were not told,” said Adams, now 40 and a stay-at-home mom in Jersey City, New Jersey, who is involved with donor-conception advocacy. “Even now, there’s still a lot of secrecy in the industry. There are still many parents who aren’t truthful or planning not to be truthful with their children.”
While some of those offspring may never know a significant part of their medical history, Adams is grateful that she does. Surprisingly, the DNA test revealed Jewish ancestry.
“There are a lot more genetic conditions that run in Jewish families, so it was really important that I get my medical history, because it’s very different from my dad who raised me,” said Adams, who has met her biological father and two of three known half-siblings. As a result of this experience, she converted to Judaism. “It has been a big journey,” she said.
In an era of advancing assisted reproduction technologies, genetics and medical history have become front and center of the debate as to whether or not egg and sperm donations should be anonymous – and whether secrecy is even possible in many cases.
Obstacles to staying anonymous
People looking to become parents can choose what’s called an “identity-release donor,” meaning their child can receive information about the donor when he or she turns 18. There’s no way to ensure that the donor will consent to a relationship at that time. Instead, if a relationship between the donor and child is a priority, parents may decide to use a known donor.
The majority of donors want to remain anonymous, said reproductive endocrinologist Robert Kiltz, founder and director of CNY Fertility in Syracuse, New York. “In general, egg and sperm donation is mostly anonymous, meaning the recipient doesn’t know the donor and the donor doesn’t know the recipient.”
Even if the donor isn’t disclosed, though, the mystery may become unraveled when a donor-conceived person undergoes direct-to-consumer genetic testing through ancestry databases, which are growing in number and popularity. These services offer DNA testing and links to relatives with identifiable information.
In the future, another obstacle to anonymity could be laws that prohibit anonymous sperm and egg donations, if they catch on. In June, Colorado became the first state in the nation to ban anonymous sperm and egg donations. The law, which takes effect in 2025, will give donor-conceived adults the legal authority to obtain their donor’s identity and medical history. It also requires banks that provide sperm and egg collection to keep current medical records and contact information for all donors. Meanwhile, it prohibits donations from those who won’t consent to identity disclosures.
“The tradition of anonymous sperm or egg donation has created a vast array of problems, most significantly that the people thus created want to know who their mommy and daddy are,” said Kenneth W. Goodman, professor and director of the Institute for Bioethics and Health Policy at the University of Miami Miller School of Medicine.
“There are counter arguments on both sides. But the current situation has led to great uncertainty and, in many cases, grief,” Goodman said.
Donors should bear some moral responsibility for their role in reproduction by allowing their identity to be disclosed to donor-conceived individuals when they turn 18, Goodman added, noting that “there are counter arguments on both sides. But the current situation has led to great uncertainty and, in many cases, grief.”
Adams, the Jersey City woman who learned she was Jewish, has channeled these feelings into several works of art and performances on stage at venues such as the Jersey City Theater Center. During these performances, she describes the trauma of “not knowing where we come from [or] who we look like.”
In the last five years, Kathleen “Casey” DiPaola, a lawyer in Albany, New York, who focuses her practice on adoption, assisted reproduction and surrogacy, has observed a big shift toward would-be parents looking to use known sperm donors. On the other hand, with egg donation, “I’m not seeing a whole lot of change,” she said. Compared to sperm donation, more medical screening is involved with egg donation, so donors are primarily found through fertility clinics and egg donor agencies that prefer anonymity. This leads to fewer options for prospective parents seeking an egg donor with disclosed identity, DiPaola said.
Some donors want to keep in touch
Rachel Lemmons, 32, who lives in Denver, grew interested in becoming an egg donor when, as a graduate student in environmental sciences, she saw an online advertisement. “It seemed like a good way to help pay off my student loan debt,” said Lemmons, who is married and has a daughter who will turn 2-years-old in December. She didn’t end up donating until many years later, after she’d paid off the debt. “The primary motivation at that point wasn’t financial,” she said. “Instead, it felt like a really wonderful way to help someone else have a family in a few weeks’ time.”
Lemmons originally donated anonymously because she didn’t know open donations existed. She was content with that until she became aware of donor-conceived individuals’ struggles. “It concerned me that I could potentially be contributing to this,” she said, adding that the egg donor and surrogacy agency and fertility clinic wouldn’t allow her to disclose her identity retroactively.
Since then, she has donated as an open donor, and kept in touch with the recipients through email and video calls. Knowing that they were finally able to have children is “incredibly rewarding,” Lemmons said.
When to tell the kids
Stanton Honig, professor of urology and division chief of sexual and reproductive medicine at Yale School of Medicine, said for years his team has recommended that couples using donor sperm inform children about the role of the donor and their identity. “Honesty is always the best policy, and it is likely that when they become of age, they might or will be able to find out about their biological sperm donor,” he said. “Hiding it creates more of a complicated situation for children in the long run.”
Amy Jones, a 45-year-old resident of Syracuse, N.Y., has three children, including twins, who know they were conceived with anonymous donor eggs from the same individual, so they share the same genetics. Jones, who is a registered nurse and asked for her real name not to be published, told them around age seven.
“The thought of using a known donor brought more concerns—what if she wanted my babies after they were born, or how would I feel if she treated them as her own every time I saw her?” said Jones.
“I did a lot of reading, and all psychologists said that it is best to start the conversation early,” she recalled. “They understood very little of what I was telling them, but through the years, I have brought it up in discussion and encouraged them to ask questions. To this day, they don't seem to be all that interested, but I expect that later on in life they may have more questions.”
Jones and her husband opted to use a donor because premature ovarian failure at age 27 had rendered her infertile. “The decision to use an egg donor was hard enough,” she said. “The thought of using a known donor brought more concerns—what if she wanted my babies after they were born, or how would I feel if she treated them as her own every time I saw her?”
Susan C. Klock, a clinical psychologist in the section of fertility and reproductive medicine at Northwestern University Feinberg School of Medicine, said, “Anonymity is virtually impossible in the age of direct-to-consumer genetic testing.” In addition, “selecting an identity-release donor is typically not the first thing parents are looking at when they select a donor. First and foremost, they are looking for a donor with a healthy medical background. Then they may consider donor characteristics that resemble the parents.”
The donor’s medical history can be critical
Donor agencies rely on the self-reported medical history of egg and sperm donors, which can lead to gaps in learning important information. Knowing a donor’s medical history may have led some families to make different or more well-informed choices.
After Steven Gunner, a donor-conceived adult, suffered from schizophrenia and died of a drug overdose at age 27 in 2020, his parents, who live in New York, learned of a potential genetic link to his mental illness. A website, Donor Sibling Registry, revealed that the sperm donor the couple had used, a college student at the time of donation, had been hospitalized during childhood for schizophrenia and died of a drug overdose at age 46. Gunner’s story inspired Steven’s Law, a bill that was introduced in Congress in July. If passed, it would mandate sperm banks to collect information on donors’ medical conditions, and donors would have to disclose medical information the banks weren’t able to find.
With limited exceptions, the U.S. Food and Drug Administration requires donors to be screened and tested for relevant communicable disease agents and diseases such as HIV, hepatitis viruses B and C, the Zika virus and several STDs. With current technology, it is also impossible to screen for thousands of rare genetic diseases. “If a couple is using IVF (in vitro fertilization) to conceive with the donor gamete, some may opt for pre-implantation genetic testing to assess for chromosomal abnormalities,” Klock said.
Even these precautions wouldn't cover every disease, and some would-be parents don't get the genetic screening. In a situation where one donor has a large number of offspring, it is concerning that he or she can spread a rare disease to multiple people, said Nick Isel, 37, of Yorkville, Illinois, who was conceived with donor sperm due to his parents’ fertility issues. They told him the truth when he was a teenager, and he found his biological father with a journalist’s help.
Since 2016, Isel, who owns a roofing company, has been petitioning the FDA to extend the retention of medical records, requiring the fertility establishment to maintain information on sperm and egg donors for 50 years instead of the current 10-year mandate.
“The lack of family health information,” he said, “is an ongoing, slow-motion public health crisis since donor conception began being regulated by the FDA as a practice.”