Why people vaccinated against COVID-19 continue to be infected

A wedding in Oklahoma has infected 15 guests vaccinated with the coronavirus. The loud July 4 celebrations spread the virus from Provincetown to dozens of locations across the country, sometimes carried by fully vaccinated attendees.

As the Delta variant is scattered all over the country, reports infections in vaccinated people have become more and more frequent, including, most recently, at least six Texas Democrats, a White House aide, and an assistant congressman Nancy Pelosi.

The highly contagious variant, combined with a staggered vaccination campaign and the near absence of preventive restrictions, is leading to a rapid increase in cases in all states and hospitalizations in almost all of them. It now accounts for about 83 percent of infections diagnosed in the United States.

But as worrying as the trend may sound, breakthrough infections – those that occur in people vaccinated – remain relatively rare, experts said, and those that cause serious illness, hospitalization or death even more. More than 97% of people hospitalized for Covid-19 are not vaccinated.

The message remains: “If you are vaccinated, you are protected,” said Dr. Celine Gounder, an infectious disease specialist at Bellevue Hospital Center in New York. “It will not end in serious illness, hospitalization or death.”

Reports of infections should not be taken to mean that vaccines do not work, Dr Anthony S. Fauci, the Biden administration’s senior pandemic adviser, told a press conference on Thursday.

“This does not in any way mean that you are dealing with a failed vaccine,” he said. “The success of the vaccine depends on the prevention of disease.”

However, people who have been vaccinated can get extremely asymptomatic or mild infections. It may surprise many Vaccinated Americans, who often assume they are fully protected against the virus. And progressive infections raise the still unresolved possibility that vaccinated people could pass the virus on to others.

Given the prevalence of the virus in much of the country, some scientists say it’s time to vaccinated people consider wearing masks indoors and in crowded spaces such as shopping malls or concert halls, a recommendation that goes beyond current guidelines from the Centers for Disease Control and Prevention (CDC), which recommend masking only for unvaccinated people.

The agency does not plan to change its guidelines unless there is a significant change in science, said a federal official who spoke on condition of anonymity because he was not authorized to s ‘express on the matter.

The agency’s advice already gives local leaders the freedom to adjust their policies based on transmission tariffs in their communities, he added. Citing the emergence of the Delta variant, health officials in several California jurisdictions are already calling for a return to the interior masking – Los Angeles County requires it.

“Seat belts reduce risk, but we must always drive safely,” said Dr. Scott Dryden-Peterson, infectious disease physician and epidemiologist at Brigham & Women’s Hospital in Boston. “We’re still trying to figure out what safe driving in the Delta was and what we should be doing.”

The uncertainty about Delta is due in part to its difference with the previous versions of the coronavirus. Although its mode of transmission is the same, it is inhaled, usually internally; Delta 15 is believed to be roughly the twice as contagious as the original virus.

Significantly, preliminary evidence also suggests that people infected with the Delta variant may carry around a thousand times more viruses than those infected with the original virus. While that doesn’t seem to mean they’re getting sicker, it probably means they’re more contagious and for longer.

The dose is also important: a vaccinated person exposed to a low dose of the coronavirus may never be infected, or may not be significantly infected. A vaccinated person exposed to extremely high viral loads of the Delta variant is more likely to have their immune system overwhelmed.

The problem worsens as transmission rates in the community increase, as exposure will increase in dose and number. Immunization rates in the country have stagnated, with less than half of Americans fully immunized, leaving the virus with plenty of room to spread.

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