This summer should have been different. Flush with the world’s best Covid-19 vaccines, America could have inoculated its way out of the pandemic. But as the highly virulent delta variant has rampaged through a half-vaccinated country, infections have surged, mask guidance has been duly revised and, most disconcertingly, calls for vaccine boosters are gaining decibels as breakthrough infections (a Covid infection in a fully vaccinated person) rise.
The issue of boosters will likely gain greater prominence after the Centers for Disease Control and Prevention warned Friday that new data on the delta variant shows how the “war has changed” against the coronavirus. While the CDC’s description of a strain that is more contagious and likely more severe than its predecessors wasn’t completely unexpected, the stunning transmissibility of breakthrough infections that the delta variant is responsible for will prompt discussions on whether booster shots can stem them and once again restore the impenetrable immunity of vaccinated people.
Even before the CDC findings were announced, the case for an extra jab was already gaining steam after data from Israel, where delta is also the dominant strain, recently showed that its vaccinated population was increasingly vulnerable to breakthrough infections. The Health Ministry found that the Pfizer shot was only 39 percent effective in preventing symptomatic Covid infection from late June to mid-July, a nosedive from levels seen this winter and early spring. Though the study was small and covered a narrow window of time, the country announced Thursday it was going to start offering a booster to Israelis over 60 who were vaccinated more than five months ago.
The decision echoed concerns amplified by Pfizer and fellow vaccine-maker Moderna about declining vaccine effectiveness over time and their promotion of boosters as a way to lift the body’s flagging immunity. Armed with new data on Wednesday, Pfizer claimed a third shot would strongly enhance protection via antibodies — proteins circulating in the blood that bind to the virus and neutralize it — against the supercontagious delta variant.
But the statements of pharmaceutical companies run counter to the realities of medical science and insult the sophistication of the body’s immune system. After creating wondrous vaccines whose efficacy far exceeded even the most optimistic expectations, Pfizer seems to be attempting to create a new multibillion-dollar need for boosters that does not clearly exist outside older people or people who are immunocompromised.
For now, the shots already administered are priming immune systems to defeat Covid and fulfilling their objective of staving off hospitalizations and death. While this is welcome news for the health of the vaccinated populace, it’s troubling for the pharmaceutical companies’ bottom lines: After all, the more doses a person requires, the more money they pocket.
As Covid decimated America’s hospitals and became the third-leading cause of death in 2020, Pfizer and Moderna were among those that responded by producing powerful vaccines that not only made the worst Covid outcomes exceedingly rare, but also greatly reduced the possibility of simple infection and the development of symptoms. While this scientific achievement was welcomed and hailed, the remarkable potency also created unrealistic expectations for what a vaccine is capable of and intended to achieve.
“The promise of all vaccines is against severe disease, hospitalization and death,” said Monica Gandhi, a professor of medicine at the University of California, San Francisco. “There was never a promise for sterilizing immunity,” meaning the complete absence of infection and symptoms, she noted. “That’s the disappointment going on in the public right now.”
The crucial finding is that against even the more formidable delta variant, Pfizer’s vaccine continues to provide protection from the worst outcomes. In a British study published last week in the New England Journal of Medicine on the effectiveness of two Pfizer shots against the delta variant, the vaccine was found to be 88 percent effective in guarding against symptomatic disease and, though not published in the results, presumably higher in preventing severe disease.
Though the Israeli figures have limitations, they also found Pfizer’s inoculant to be more than 90 percent successful against serious disease. Additionally, a study published in the New England Journal of Medicine on Wednesday found that breakthrough infections in Israeli health care workers were mostly mild or asymptomatic.
These numbers should provide reassurance when we hear of a spike in still-rare breakthrough infections (2.6 percent in the Israeli health care workers described in the study published Wednesday), which will happen as the vaccinated pool expands amid ubiquitous and sensitive PCR testing, loosening public health measures and an uber-contagious delta variant. Even a small percentage of cases in the United States’ nearly 165 million fully vaccinated individuals will look like many people. But despite this uptick, unvaccinated people account for nearly all of the country’s hospitalizations and deaths during a phase of the pandemic in which the delta variant is fully ascendant.
None of this, though, has prevented a daily peppering of alarming reports and selective studies that vaccinated immunity is weakening as circulating antibodies induced by vaccination decline over time. Though antibody tests are readily available, easy to measure and provide instant gratification, their assessment isn’t entirely illuminating at this point. While they have historically been a crucial gauge to assess other kinds of vaccines, we still lack full knowledge on how informative they are about the efficacy of the revolutionary mRNA mechanism the Pfizer and Moderna vaccines use.
“We know the antibody response from these vaccinations is waning, but we don’t know what the protective threshold is. We just don’t have enough information on these mRNA vaccines,” said Mark Slifka, a vaccinologist at Oregon Health and Science University. “All of our other vaccine-preventable diseases are prevented by antibodies, and that’s why people are focusing on that.”
Regularly forgotten is that these antibodies represent just one layer of a complexfortress designed to thwart Covid’s assault on the body. Even as these antibodies disappear in the months following inoculation, an adaptive system of immunity that was trained by the Covid vaccine remains intact and ready to pounce within days or less if the virus is detected in the body.
This long-term immunity is undergirded by two types of cells that operate after the initial wall of antibodies is breached. While the enduring virus may cause symptoms at this stage, this other arm of the immune system will work to arrest Covid’s further advances and prevent serious illness.
One of them, memory B cells, produce a multitude of additional antibodies. The other, T cells, directly target and destroy virus-infected cells independently of antibodies. The mRNA vaccines stimulate “robust” and persistent production of memory B cells after vaccine administration. These vaccine-charged memory B cells can recognize different Covid variants. And finally, vaccine-induced T cells not only guard against severe disease but also remain strong versus variants.
“The memory B cells are a great backup response for anything that slips past the antibodies like these neutralizing escape variants,” Slifka said. “That’s the nice thing about these backup mechanisms: They hit the target from multiple angles.”
This is not to say there will be no eligible arms needing Covid booster jabs. In time, groups such as immunocompromised people and older people, whose responses to vaccines are impaired or not as robust, will likely benefit from these extra shots to maintain their defenses. But as we move forward in a world in which Covid becomes a part of our daily lives, science rather than the avarice of pharmaceutical executives must be our propelling force on matters of vaccines and public health.
“The CEOs of companies are the main messengers on boosters as opposed to scientists. Those who stand to profit get to message,” Gandhi asserted. “We need to clear ourselves of conflict of interest before we discuss this problem.”