NEW HAVEN, Conn. (WTNH) — There is new evidence on how dangerous getting reinfected with COVID-19 can be.

“I think this study suggested that reinfections may not be that benign,” Yale Medicine Infectious Diseases Physician Albert Shaw said.

The study was done by the Department of Veterans Affairs and involved 40,000 people with COVID-19. It showed that for people who had two or more episodes of the virus, their risk of hospitalization and death went up two to three times. They were also more at risk for impacts to their heart, lungs, kidneys and nervous system.

The study included those who were vaccinated and unvaccinated for the virus.

Shaw urges caution as the holidays approach by getting the latest updated COVID-19 booster and masking in crowded places.

Another new study is about how COVID-19 affects the immune system. Scientists are studying if it makes you more vulnerable to other winter viruses.

“In some cases, there is some evidence that changes in cells of the immune system, white blood cells and the genes they express can be affected either weeks or even months after recovery,” Shaw said. “Even in people that don’t have necessarily symptoms of long COVID.”

COVID-19 deaths worldwide are down significantly since February. The World Health Organization reported 9,400 deaths last week. That’s 88% lower than the 75,0000 deaths in one week last February.

Shaw credits vaccines and antiviral treatments to the drop, but has a local reminder.

“In Connecticut last week, there are still 50 deaths attributed to COVID,” he said. “And, so I think there’s still too many of our friends and neighbors, and so especially with the holidays coming up, you know, really encourage people to take steps to protect yourselves in your family.”

And some positive news about the new COVID-19 updated bivalent booster shots. They are finally catching on, with more than 5 million administered in the past week, the highest seven-day total since January.