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Antibody-assisted vaccination will speed up the path to protection

AAfter almost a year of pandemic terror, the end is in sight. But you still have to narrow your eyes.

The FDA has authorized the emergency use of two safe and effective vaccines that science has delivered at record speeds. The question now is: How do we best distribute them?

The Advisory Committee on Immunization Practices of the Centers for Disease Control and Prevention (ACIP) has published guidelines that vaccinations should be started by healthcare professionals and residents of long-term care facilities, followed by other key workers and those over 75 years of age. Only as a sub-priority is mentioned how the history of Covid-1

9 infection should affect the location of the line: ‘HCP with documented acute SARS-CoV-2 infection in the previous 90 days may choose to postpone vaccination until the end of 90 days, to facilitate vaccination of those HCPs that remain susceptible. “


Given the low risk of reinfection and the limited supply of vaccine doses, it would be a mistake not to make the previous infection a more central consideration in our vaccine prioritization. With approximately 75 million Americans who have already been infected with SARS-CoV-2, but only 24 million know, the use of a large-scale study of Covid-19 antibodies can help better target the distribution of vaccines to those with the highest levels. high risk. This can save lives and return us to normal sooner.

This strategy is based on the two biggest discoveries made in the effort against the virus. The first is that after infection, including mild and asymptomatic infections, there appears to be lasting and strong immunity for up to six months or more. The fact that there are nearly 100 million confirmed cases of Covid-19 worldwide and only a few documented re-infections provides convincing evidence of lasting immunity. And even among the rare reinfections, their course will probably be easier thanks to the memory of the immune system.


The second breakthrough was the huge success of the development of the Covid-19 vaccine.

This combination of lasting immunity and effective vaccines is the cornerstone of almost all past successes against viruses (HIV is so far the key exception). In this way, the plagues of smallpox, polio, measles, mumps and other infectious diseases are beaten. And here’s how we beat Covid-19.

But even in the best case, it will be months before enough doses of vaccine are made to treat everyone. Since epidemiologists estimate that two-thirds of the population must be immunized to protect the herd needed to quell the pandemic, the 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 have never been diagnosed with Covid-19. This is especially true for countries that are most affected by the virus. For example, in New York State, it is estimated that 30% of the population has recovered from Covid-19, while only 7% have been diagnosed with the virus. Insufficient diagnosis is not limited to locations like New York that have had an early tide. More than 36% of North Dakotans are considered infected, while only 13% are diagnosed. Given these discrepancies, in countries like North Dakota, without the help of antibody testing, I believe that up to 1 in 4 vaccines can be given to someone who is currently immunized against Covid-19.

Although the presence of antibodies is not a perfect measure of immunity, due to both the rarity of reinfection and the accuracy of current antibody tests (with false positive levels of about 1% or lower), those with antibodies can be safely considered for low-risk group. This reality was further confirmed in a recent report by the New England Journal of Medicine at Oxford University, which followed 12,000 health workers for 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 difficulty in the United States, large-scale PCR tests have been performed, and with the early dispersal of vaccines, efforts to test antibodies to the public may sound silly. Is not.

In terms of antibody scaling testing, the process is completely different from the PCR-based testing used to detect acute infection. Antibody tests are more like traditional blood work and are processed as automated immunoassays. This means that they can be managed on large batches of machines that almost all functional medical laboratories already own and can use the existing collection infrastructure for collection and processing laboratories. As Benjamin Maser, a pathologist at Hopkins Hospital, told me, “The delays we’ve encountered with PCR testing shouldn’t stop people from testing for antibodies if necessary. The antibody test is much easier 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, combined with canceled surcharges for others in clinical and commercial laboratories, can further expand access. Batch tests based on schools and employers can inform about their future vaccination campaigns.

To be clear, it is safe and useful for those previously vaccinated with SARS-CoV-2 (just as adults suffering from chickenpox need a booster to prevent shingles). It is paramount to make the right investments to support both tests and vaccination. These efforts must be complementary, not competitors. And if access to antibody testing is not readily available, 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 the antibody-assisted approach will allow the United States to reach herd immunity faster. Or to revive our economy faster. Or rather, protect more front-line workers – nurses, teachers, groceries, delivery drivers, firefighters and more.

But for me, I suspect, it’s a lot less abstract for you than that. For each vaccine we save with an antibody test, there will be another that we can give to the higher-risk individual who is looking forward to it or his turn in line. And we all have loved ones standing in line: an elderly grandparent, a mother with an immune deficiency, or a cousin battling cancer.

Given everything we’ve done so far to protect them – postponed meals, canceled vacations and missed hugs – we need to use every weapon in our armature against this plague. This includes antibody testing.

Michael Rose is a resident physician in internal medicine and pediatrics at Johns Hopkins University School of Medicine.

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