With ‘breakthrough infections’ among vaccinated people being the new COVID-19 pandemic concern, experts say the numbers of those contracting the virus despite being inoculated highlight the danger that unvaccinated people pose to the general public.
Across the globe, the coronavirus has constantly evolved through mutation, causing new variants to emerge. Multiple variants of the virus have already been documented since the pandemic’s onset as the it continues to infect and pass on from one individual to another.
The dominant variant at present is the highly contagious Delta strain of COVID-19. New and more contagious variants of the coronavirus have been a concern for many as they could potentially pose a threat to vaccine efficacy.
Dr. Rochelle Walensky, director of the Centers for Disease Control and Prevention (CDC), told reporters on Tuesday: “On rare occasions, some vaccinated people infected with the Delta variant after vaccination may be contagious and spread the virus to others.”
This new science is worrisome, according to Dr Drew Weissman, a physician and infectious disease expert at the University of Pennsylvania.
He said the amount of breakthrough cases being seen suggest that the vaccines “are still working great,” but “too much is being asked of them.”
Variants vs. vaccines
Mounting research suggests the variants are placing greater strain on the vaccines. When people are infected with the Delta variant, they produce a thousand times greater viral load than seen from the original COVID-19 strain.
That means the Delta variant is more efficient at spreading and every time an infected person coughs, sneezes or speaks, they potentially release much more of the virus — and opportunities to get someone else sick — than earlier in the pandemic.
In places like the US, where only about half of the nation’s population — 163.3 million people — are fully vaccinated against the coronavirus, the vaccine’s advantages begin to erode, Weissman said. And in some pockets of the country, fewer than a third of people have received full vaccine protection.
“You can’t control a pandemic when 30 percent or even half the people are immunized,” he told news channel PBS.
Dr. Alex Huffman, an aerosol scientist and professor at the University of Denver, said it is important to note that no vaccine is 100 percent effective at preventing disease and that occasional breakthroughs are expected with any vaccine.
While peoples’ knowledge of vaccines has increased considerably throughout the many months of the pandemic, a portion of the public have been exposed to misinformation about the safety and effectiveness of COVID-19 vaccines — including that breakthrough infections somehow mean that they do not work – obscuring how they and others perceive those risks, experts say.
However, Project HOPE’s Chiefl Health Officer and former CDC Director of Global Health, Dr. Tom Kenyon, told Al Arabiya English, vaccines still offer the best protection against the virus.
“We still don’t have all the answers and need more research, but it’s urgent for people to get vaccinated as soon as possible if they can in order to protect themselves, their families and loved ones from these new variants.”
Vaccines: A frontline defense
Other health experts believe while vaccines are the best frontline defense, they should be in conjunction with other safety protocols such as face masks and social distancing.
Dr Leana Wen said she was confused on May 13 when the CDC lifted mask mandates for fully vaccinated people, easing social pressure on unvaccinated people and placing the country on the “honor system.”
“We don’t trust the honor system,” said Wen, an emergency physician and public health professor at George Washington University and a former public health commissioner for Baltimore, told PBS. “The unvaccinated are now putting the vaccinated at risk.”
Even with Delta, almost everyone who has died from COVID-19 — 99.5 percent of known cases — are unvaccinated people, along with 97 percent of people hospitalized for the illness.
That suggests that the vaccines are still highly effective, US Surgeon General Dr Vivek Murthy said during a recent press briefing.
The CDC is counting vaccinated people who have been hospitalized or died from the coronavirus.
Based on data available so far, that is still a relatively rare scenario.
In a study published July 28 in the New England Journal of Medicine, researchers analyzed results from nasal swab tests collected from 1,497 fully vaccinated health care workers at Israel’s largest medical center, with the last tests gathered by April 28, when the alpha variant was taking hold in Israel. They found 39 breakthrough infections.
Those who were infected presented mild symptoms, if any at all, the study authors wrote. And these results were finalized months before the Delta variant dominated the pandemic.
In a July 21 study published in the same journal, researchers noted there were “only modest differences in vaccine effectiveness” between people exposed to the alpha variant versus the Delta variant.
However, in the US, no one knows exactly how many breakthrough cases there really are because nationwide data doesn’t exist.
Greater research needed
Dr. Ashish Jha, dean of Brown University’s School of Public Health, describes that as problematic, because the way researchers count infections among vaccinated people is vital to investigating this continually evolving virus.
“One of the most critical questions is how much forward-transmission is happening from breakthrough infections,” Jha said. “That’s something I don’t feel like we have a good grip on and is absolutely essential to understand.”
The risk of a breakthrough infection for vaccinated people with symptoms upon exposure to the Delta variant is reduced by seven-fold and that reduction is 20-fold for hospitalizations and death, Dr Walensky, of the CDC, said Tuesday.
However, the CDC does track cohorts of fully vaccinated essential workers, including those in the health care and long-term care industries, to better understand how protective vaccines are.
Dr. Anthony Fauci, the White House’s chief medical advisers said on Tuesday that, from those cohorts, they are seeing data showing that fully vaccinated people who get infected “clearly can transmit it to other people.”
Vaccine companies have been exploring the idea of booster shots to provide better protection, if needed, in the future.
The Pfizer-BioNTech vaccine‘s efficacy, previously at 93 percent, was deemed less effective in breakthrough cases in a statement released by the partners, citing Israel health ministry data on the matter.
The data revealed that the vaccine was only around 64 percent effective at protecting against breakthrough infections.
However, according to the New York Times, this data has not been peer-reviewed and may be more complex due to several variables, one of them being that the Delta variant was not yet widespread at the time.
However, for many, the more people vaccinated, the better the chance to reduce COVID-19 cases, including breakthrough infections.
“Roughly 99 percent of people who are hospitalized and killed by this virus are unvaccinated,” Professor at the University of Pennsylvania and member of the Food and Drug Administration (FDA) vaccine advisory panel, Dr. Paul A. Offit said.
“You’re not really trying to prevent asymptomatic or mild symptoms. You’re trying to keep people out of the hospital and out of the morgue. It’s a goal we’ve met remarkably well.”