ONEafter almost a year of pandemic terror, the end is in sight. But you still have to skew.
The FDA has granted permission for emergency use of two safe and effective vaccines that science has delivered at record speed. The question now is: How do we best distribute them?
The Centers for Disease Control and Prevention’s Advisory Committee on Immunization Practices (ACIP) has published guidance that vaccinations should start with healthcare professionals and residents in long-term care facilities, followed by other key frontline workers and those over 75 years old. Mentioned only as a sub-priority is how a history of Covid-1
Given the low risk of reinfection and the limited supply of vaccine doses, it would be a mistake not to make previous infection a more central consideration in our vaccine priorities. With an estimated 75 million Americans already infected with SARS-CoV-2, but only 24 million knowing it, using comprehensive Covid-19 antibody testing can help better target vaccine delivery to those at greatest risk. This can save lives and bring us back to normalcy faster.
This strategy is based on the two biggest discoveries made in the fight against the virus. The first is that after infection, including mild and asymptomatic infections, immunity and strong immunity appear for up to six plus months. The fact that there have been nearly 100 million cases of Covid-19 confirmed worldwide, and only a handful of documented re-infections provide compelling evidence of lasting immunity. And even among the rare gene infections, their course is likely to be milder thanks to the memory of the immune system.
The second breakthrough is the resounding success of Covid-19 vaccine development.
This combination of lasting immunity and effective vaccines has been the cornerstone of almost all previous successes against viruses (HIV so far is the main exception). It is such that the fungi, polio, measles, mumps and other infectious diseases have been beaten. And that’s how we should beat Covid-19.
But even at best, it will take months before enough vaccine doses have been made to treat everyone. As epidemiologists estimate that two-thirds of the population must be immune to the herd protection needed to quell the pandemic, an antibody-assisted approach will allow us to reach this threshold more quickly.
Here is another reason why an antibody-assisted approach to vaccination is needed: Due to the combination of inadequate testing and asymptomatic infection, most people infected with Covid-19 are never diagnosed with it. This is especially true in states hardest hit by the virus. In the state of New York, for example, it is estimated that 30% of the population has recovered from Covid-19, while only 7% have been diagnosed with the virus. Underdiagnosis is not limited to localities like New York, which had an early rise. More than 36% of North Dakotans are estimated to be infected, while only 13% have been diagnosed. Given these discrepancies in states like North Dakota without the help of antibody testing, I estimate that as many as 1 in 4 vaccines could be given to a person who is currently immune to Covid-19.
Although the presence of antibodies is not a perfect measure of immunity, thanks to both the rarity of reinfection and the accuracy of the current antibody test (with false positive frequencies around 1% or less), those with antibodies can be safely considered as a low-risk group. This reality was further confirmed in a recent report from the New England Journal of Medicine from Oxford University, which followed 12,000 healthcare professionals over six months and found no symptomatic infections in those with antibodies to SARS-CoV-2.
But theory and practice are two different things. With the difficulties that the United States has had in scaling PCR tests, and with early nebulization of vaccine distribution, efforts to test scores of the public for antibodies may sound bad. It is not.
In terms of antibody test scaling, the process is quite different from the PCR-based test used to detect acute infection. Antibody samples resemble more traditional blood work and are treated as automated immunoassays. This means that they can be run in large batches on machines that almost all functional medical laboratories already own, and can use existing laboratory collection infrastructure for collection and processing. As Benjamin Mazer, a pathologist at Johns Hopkins Hospital, told me, “The delays we have had with PCR testing should not deter people from taking antibody tests if they are necessary. The antibody test is much simpler to perform and can be reversed in hours instead of days. ”
An easy place to start would be to test for antibodies in people who already need laboratory tests for other reasons, such as when they are admitted to a hospital, emergency department or have a clinic appointment. Standing orders paired with canceled refunds to others in clinical and commercial laboratories may further expand access. School- and employer-based batch testing can inform their future vaccination campaigns.
To be clear, it is both safe and beneficial for those previously infected with SARS-CoV-2 to be vaccinated (just as adults who had chickenpox need a booster to prevent shingles). It is crucial that appropriate investments are made to support both tests and vaccination. This effort must be a supplement, not a competitor. And if access to antibody tests is not readily available, vaccination should never be delayed. Finally, when we have enough supply to meet public demand, everyone should be vaccinated, regardless of antibody status.
I could conclude with an argument about how an antibody-assisted approach would enable the United States to achieve herd immunity faster. Or revive our economy faster. Or protect more front-line workers – nurses, teachers, grocers, delivery drivers, firefighters and others – faster.
But for me, and I suppose for you too, it is much less abstract than that. For every vaccine we save using antibody testing, there will be one more we can give to someone at higher risk waiting anxiously for her or his turn in the queue. And we all have loved ones standing in line: an elderly grandparent, an immunocompromised mother, or a cousin fighting cancer.
Given everything we have done so far to keep them safe – postponed dining, canceled vacations and missing hugs – we must use every weapon in our armament area against this plague. This includes testing for antibodies.
Michael Rose is a resident physician in internal medicine and pediatrics at Johns Hopkins University School of Medicine.