NEW YORK－About 60 percent of the population in the United States is heading into the winter months with reduced protection against the coronavirus, the US Centers for Disease Control and Prevention said in data released last week.

Health experts warned that those who were vaccinated early in the year are likely to have waning immunity.

About 6 in 10 US citizens are now fully vaccinated, with more than half having received their last shot more than six months ago, the threshold recommended for a Moderna or Pfizer booster. However, the CDC said if combined with the 100 million unvaccinated people, only 40 percent of people in the US are at their strongest immunity level against COVID-19.

As of Saturday morning, more than 229.2 million people had received at least one dose of a COVID-19 vaccine, making up 69.1 percent of the whole US population. More than 195.9 million were fully vaccinated, accounting for 59 percent of the total.

The New York Times reported that the seven-day average of confirmed cases stood at 93,196 nationwide on Friday, with the 14-day change striking a 30 percent rise. There were 1,687 deaths related to COVID-19 on Friday, according to the CDC.

More shockingly, according to two new studies published by the CDC on Friday, pregnant women infected with the Delta variant are at increased risk of having a stillbirth or dying during childbirth. The research expanded on reports from doctors nationwide who have noted a rise in pregnant women becoming critically ill with COVID-19, particularly as the highly contagious variant has taken hold.

"We are seeing loads of pregnancy complications from COVID-19 infection," said Ellie Ragsdale, director of fetal intervention at the UH Cleveland Medical Center. Complications include premature deliveries, abnormally high blood pressure in pregnant women, as well as pregnancy loss.

Stillbirth risk

One of the new studies analyzed more than 1.2 million deliveries nationwide between March 2020 and September 2021. Stillbirths were rare in the US before the pandemic, at a rate of 0.59 percent. Those rates remained similar even when the pandemic hit, at 0.64 percent among women who were never diagnosed with COVID-19.

But the rate of stillbirths rose to 0.98 percent among expectant mothers infected with the coronavirus. And once the Delta variant took hold in July, the rates rose with 2.7 percent of COVID-19 positive pregnancies ending in stillbirth.

In an interview at the Bloomberg New Economy Forum on Wednesday, Bill Gates, co-founder of Microsoft, listed two key steps that he thought can help conquer COVID-19: continue to vaccinate the rest of the world, and use up-and-coming antiviral drugs to prevent severe disease and death.

Ending the pandemic does not mean eradicating COVID-19 completely, Gates said. Rather, "We'll be able to bring it down to very small numbers by the end of 2022." That target remains realistic, given advances in vaccines and antiviral drugs. For starters, "the vaccines are very good news", Gates said.

Xinhua