With one in four adults in the United States now fully vaccinated against COVID-19, departments of health and scientific studies have documented what are known as “advanced” cases or people who became infected or ill despite having been vaccinated.
Such cases are exceptionally rare, but to be expected, experts say.
“You will see advanced infections in any vaccination when you vaccinate literally tens, tens and tens of millions of people,” Dr. Anthony Fauci said during a White House press conference on March 26th. “In some ways, it’s not surprising,” Fauci said.
COVID-19 vaccines are highly effective, but none are 100% effective, meaning a small number of people can become infected after being completely vaccinated, but these infections are usually mild or asymptomatic.
Dr. William Schaffner, a professor of preventive medicine and infectious diseases at Vanderbilt University Medical Center, considered the efficacy rates of approximately 95% of Pfizer and Moderna vaccines to be “spectacularly effective.” In clinical trials, vaccines were virtually 100% effective in keeping people out of the hospital, he added, noting that “there were still some milder infections that did occur.”
How common are “advanced” cases of COVID-19?
“It’s pretty rare,” said Dr. Shira Abeles, an infectious disease specialist at UC San Diego Health, about advanced cases. “I think it will continue to be that way,” he added.
Recent real-world studies have confirmed this low rate of progress. A study that Abeles helped conduct in Southern California between December 2020 and February 2021, found that less than 1% of the 36,600 health workers who were studied tested positive for COVID-19 after of being completely vaccinated, that is, both doses and two weeks to obtain immunity. build – with Pfizer or Modern vaccines.
According to the researchers, no vaccinated health workers who contracted COVID-19 were hospitalized or died, and those who became ill appeared to have milder symptoms than those who were not vaccinated.
An even larger investigation by the Washington State Department of Health found that of 1.2 million people who were completely vaccinated, there was evidence of 102 advanced cases, representing less than 0.01% of residents of the state. been completely vaccinated. Although most of these patients experienced mild symptoms, at least eight were hospitalized and the health department is investigating two possible advanced cases in which patients died.
How do the “advances” of COVID-19 occur?
It is not entirely clear.
Very old or immunocompromised people may be at increased risk for advanced cases, as their bodies may produce a less potent immune response to the vaccine.
“For all the vaccines we use, immunocompromised people and the elderly don’t respond as well as healthy people and younger people,” Schaffner said. In the case of the Washington state investigation into the two possible deaths from COVID, both patients were over 80 years old and had underlying health problems.
Similar to influenza, the highest risk for the elderly and immunocompromised is one of the reasons why it is important for young and healthy people to have the COVID-19 vaccine. If everyone is vaccinated, it is harder for the virus to find targets, which will protect those at higher risk.
“We should all be vaccinated to protect ourselves and protect the weakest among us,” Schaffner said.
As for advanced cases among young or healthy people, “every now and then something happens for biological reasons that we can’t fully explain,” Schaffner said.
Those who get sick after being completely vaccinated should have partial protection. Instead of going to the hospital or dying, they may have less severe symptoms, such as feeling unwell or developing a mild fever. “That’s the strength of our study,” Abeles noted. “We were screening in a population, so we detected asymptomatic diseases and mild illnesses,” he said. “Overall, that’s what you’ll see.”
Could the new variants be causing cases of progress?
Another possibility that public health agents are investigating is whether the new variants of the virus caused some of the advanced cases reported.
“One of the important things that will be done and needs to be done is to sequence the genome of the virus which is the innovative virus,” Fauci said. “It would be very important to see if they broke the wild-type virus, which would indicate a real decrease in immunity or if it was transmitted with any of the variants, which would be much more explicable if they don’t have enough cross-reactivity.”
To date, it appears that currently authorized vaccines decrease the severity of infection regardless of the strain of the virus. That is why experts say it is of utmost importance that even people previously infected with COVID get vaccinated. Knowing if the advanced cases were caused by the virus that the vaccines were designed to protect against or by new variants could inform scientists about how to address future vaccines and booster shots. If a worrying variant is being opened, laboratory scientists could develop a vaccine aimed at mutations in the variant’s peak protein, Abeles explained. If the viruses have already been exposed to the community and immunity appears to be declining, health experts could suggest a boost to the vaccine itself, he added.
“It’s a moving target and we’re still learning a lot,” Abeles said. “We will be very attentive.”
Meanwhile, it is critical to keep infection levels low so that there is less evolutionary pressure on the virus to mutate into more variants of concern. “We want to keep them in a few, instead of letting the virus have too many opportunities,” Abeles said.
Morgan Winsor of ABC News contributed to this report.