The so-called “breakthrough” COVID-19 cases are coronavirus infections that occur in people who have been fully vaccinated. Some of these cases appeared in places such as the White House and athletes gathered in Tokyo to participate in the Olympics, raising questions about the effectiveness of the vaccine, especially for the new Delta variant.

However, infectious disease experts say that there will be a small number of breakthrough cases with any type of vaccine, so it should not be a cause for concern.

The vaccine teaches the immune system to recognize invaders such as the coronavirus and attack them immediately. The existing COVID-19 vaccines are highly effective, but the possibility of infection still exists.

Factors that may affect the effectiveness of the vaccine include how much virus you have been exposed to and how strong your immune system is.

Certain health conditions and medications can also weaken the immune system’s response to vaccines. However, Dr. William Moss, a vaccine expert at the Bloomberg School of Public Health at Johns Hopkins University, said that in general, these types of breakthrough infections cause almost no symptoms. ABC News.

Data from the New England Journal study found that breakthrough infections have a lower viral load and fewer symptoms.

according to U.S. Centers for Disease Control and PreventionA person is considered fully vaccinated two weeks after the second two doses of vaccine or two weeks after receiving a single dose of vaccine.The agency reported that As of July 12, There have been 5,492 cases of breakthrough COVID-19.

However, this is not a complete number, because mild and asymptomatic cases are more difficult to track.Centers for Disease Control and Prevention Not currently recommended Routine testing of asymptomatic vaccinators.

Some health experts, such as Dr. Paul Offit, director of the Vaccine Education Center at the Children’s Hospital of Philadelphia, believe that asymptomatic or “mild” infections in fully vaccinated people should not even be considered breakthrough infections.

“I think we have misused the term breakthrough. If a fully vaccinated person is subsequently hospitalized or died of the virus, it is a breakthrough case,” Close tell NPR.

He said the important thing is that “the vaccine is still doing its job-keeping people away from hospitals and morgues.”

What about the Delta variant?

The CDC acknowledges that the prevalence of new variants like highly infectious Delta variants may play a role in these breakthrough cases, but research to date shows that the COVID-19 vaccine still has a protective effect on the new variants.

If the number of breakthrough infections starts to surge, it may indicate that immunity is declining and a booster may be needed.The country is currently experiencing a COVID-19 cases make a comeback, Health officials said, due to slowed vaccination rates and fast-moving Delta variants.

So far, the majority of COVID-19 hospitalizations and deaths in the United States belong to Not vaccinatedTo keep people still hesitant to vaccinate, Dr. Brytney Cobia, a doctor in Alabama, has been sharing her experience of caring for dying COVID-19 patients.

She is in an article Facebook posts This past Sunday, “I admitted to the hospital a young healthy person with a very serious COVID infection. The last thing they did before intubation was to ask me for a vaccine. I shook their hand and told them I’m sorry, But it’s too late.”

Then she wrote: “A few days later, when I called it the time of death, I hugged their family. I told them that the best way to remember their loved ones was to get vaccinated and encourage everyone they knew to do the same. “

Health officials continue to emphasize that vaccination is still the best way to protect yourself and your loved ones from the coronavirus (including any emerging variants).