ANafter almost a year of pandemic terror, the end is near. But you still need to squint.
The FDA has granted emergency use authorization for two safe and effective vaccines that science has distributed at record speed. The question now is: how can we best distribute them?
The Immunization Practices Advisory Committee (ACIP) of the Center for Disease Control and Prevention has issued guidelines that vaccination should begin with health professionals and residents of long-term care facilities, followed by other essential frontline workers and those with over 75 years. Mentioned only as a subpriority is how a history of Covid-19 infection should affect a person’s place in the queue: “HCP with acute SARS-CoV-2 infection documented in the previous 90 days may choose to delay vaccination until close to the end of 90 day period, in order to facilitate vaccination of HCPs that remain susceptible. ”
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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 prioritization of vaccines. With an estimated 75 million Americans already infected with SARS-CoV-2, but only 24 million aware of this, the large-scale Covid-19 antibody test can help better target vaccine allocation to those most at risk. Doing so can save lives and bring us back to normal sooner.
This strategy is based on the two biggest discoveries made in the efforts against the virus. The first is that after infection, including mild and asymptomatic infections, there appears to be strong and lasting immunity for more than six months. The fact that there have been almost 100 million confirmed cases of Covid-19 worldwide and only a handful of documented reinfections provide convincing evidence of lasting immunity. And even among rare reinfections, its course is likely to be milder thanks to the memory of the immune system.
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The second advance is the resounding success of the development of the Covid-19 vaccine.
This combination of long-lasting immunity and effective vaccines has been the cornerstone of almost all previous successes against viruses (HIV, so far, being the main exception). This is how the scourges of smallpox, polio, measles, mumps and other infectious diseases were overcome. And this is how we are going to beat Covid-19.
But even at best, it will be months before enough vaccine doses are made to treat everyone. With epidemiologists estimating that two-thirds of the population must be immune to the protection of the herd needed to contain the pandemic, an antibody-assisted approach would allow us to reach that limit faster.
Here is another reason why an antibody-assisted vaccination approach 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 the states most affected 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 places like New York, which had an early rise. It is estimated that more than 36% of Northern Dakotans were infected, while only 13% were diagnosed. Given these discrepancies, in states like North Dakota, without the help of antibody tests, I estimate that up to 1 in 4 vaccines can be administered to someone who is currently immune to Covid-19.
Although the presence of antibodies is not a perfect measure of immunity, thanks to the rarity of reinfection and the accuracy of current antibody tests (with false positive rates around 1% or less), those with antibodies can be considered low risk . group. This reality was confirmed in a recent report by the New England Journal of Medicine at Oxford University that followed 12,000 health professionals for six months and found no symptomatic infections in people with antibodies to SARS-CoV-2.
But theory and practice are two different things. With the difficulty the United States has faced for scale PCR testing and the initial spraying of vaccine distribution, efforts to test the public for antibodies may seem reckless. It is not.
Regarding the antibody scale test, the process is totally different from the PCR-based test used to detect acute infection. Antibody tests are more similar to traditional blood tests and are processed as automated immunoassays. This means that they can run in large batches on machines that almost all functional medical laboratories already have and can use the existing laboratory collection infrastructure for collection and processing. As Benjamin Mazer, a pathologist at Johns Hopkins Hospital, told me, “The delays we experience with PCR tests should not prevent people from doing antibody tests, if they are needed. 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, the emergency department or have a clinical appointment. Permanent orders paired with canceled co-payments to third parties in clinical and commercial laboratories can further expand access. School and employer-based batch tests can inform your future vaccination campaigns.
To be clear, it is safe and beneficial for those previously infected with SARS-CoV-2 to be vaccinated (just as adults who have had chickenpox need a booster to prevent herpes zoster). It is essential that adequate investments are made to support both tests and vaccination. These efforts should be complementary, not competing. And if access to the antibody test is not readily accessible, vaccination should never be delayed. Finally, once we have enough supply to meet public demand, everyone should be vaccinated, regardless of antibody status.
I could end with an argument about how an antibody-assisted approach would allow the United States to achieve collective immunity more quickly. Or revive our economy faster. Or protect more frontline workers – nurses, teachers, grocers, delivery drivers, firefighters and others – sooner.
But for me, and I suspect that for you too, it is much less abstract than that. For every vaccine we save using the antibody test, there will be one more that we can give to a high-risk individual who eagerly awaits his turn in line. And we all have loved ones in line: an elderly grandfather, an immunocompromised mother, or a cousin battling cancer.
Given everything we’ve done so far to keep them safe – deferred meals, canceled vacations and missing hugs – we must use every weapon in our arsenal against this plague. This includes testing for antibodies.
Michael Rose is a resident physician in internal medicine and pediatrics at the Johns Hopkins University School of Medicine.