The fourth wave of COVID-19 cases has arrived. Are we going to escape the fate of the UK? It is too early to know.

A doubling of COVID-19 cases in the past two weeks suggests the United States has entered a fourth wave of the pandemic.

No one knows what the next month or two will bring, but the UK example suggests the infection rate could become quite high, while hospitalizations and deaths remain relatively low.

Instead of the virus raging through entire communities, it should target the unvaccinated, including children, and if rates are high enough, also the most vulnerable of those vaccinated – the elderly and the immunocompromised.

“Given that the majority of our population is now immune, it is unlikely that we will return to the massive nationwide waves we saw in January,” said Dr David Dowdy, infectious disease epidemiologist at Hopkins Bloomberg School of Public Health. in a webinar Wednesday with the media.

But major epidemics can still occur, especially in areas with low vaccination rates.

“We are going to live in two pandemic worlds, the vaccinated world and the unvaccinated world,” said Dr. Luis Ostrosky, chief infectious disease officer at UTHealth and infectious disease specialist at Memorial Hermann-Texas Medical Center in Houston. .

The three vaccines licensed in the United States, from Moderna, Pfizer-BioNTech and Johnson & Johnson, have all been shown to be highly effective against variants of the virus, including Delta, which now accounts for most cases in the United States.

More than 99% of people currently hospitalized with COVID-19 are not vaccinated. Ostrosky said virtually all of his patients are unvaccinated and all regret not having been vaccinated.

COVID-19 may not be as deadly in this new wave, as older people are largely vaccinated and young people are less likely to die from infection, said Ravina Kullar, infectious disease specialist and epidemiologist and an adjunct faculty member at UCLA Medical Center.

But the Delta variant is significantly more contagious than the previous ones, although it’s still unclear whether it makes people sicker than the previous variants.

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“The concern about Delta is well placed,” said Dr Yonatan Grad, infectious disease specialist at Harvard TH Chan School of Public Health. “We certainly find that this wave is something to be faced with and not to be taken lightly.”

COVID-19 rates rise again

In the UK, which has roughly the same vaccination rate as the US, the seven-day average number of infections has returned to its January 20 level when the country was just a few weeks old. after its peak.

But hospitalizations there hover around 500 per day compared to 4,500 at their peak in January and deaths remain much lower, with just 26 reported across the country on Tuesday compared to the Jan. 19 peak of more than 1,300.

In the United States, infections have more than doubled since the week of June 22, with the total number of cases increasing in 48 states and deaths also starting to rise. Still, infection rates are 90% lower than they were at the January peak.

And there is yet another peak expected this fall. The coronavirus that causes COVID-19 is likely a seasonal virus, which means, like the flu, people are more vulnerable to it in the fall and winter. No one knows when that start date will be, Grad said.

With about 80% of those over 65 fully vaccinated in the United States, young people make up a higher percentage of those who get sick. And while children under the age of 12 are unlikely to contract a severe case of COVID-19, they cannot get vaccinated and therefore remain vulnerable to the Delta variant.

“Due to the fact that children do not have the opportunity to be vaccinated at the same level as adults, I think they will experience a disproportionate burden of infection and disease from the delta variant,” said Dowdy. .

Vaccines are good, but not perfect. People who become infected with COVID after vaccination, even if their infection is so mild that they don’t notice it, could be contagious, but likely less so than those who are not vaccinated, Grad said.

Three Yankees pitchers – who had all been vaccinated – tested positive for COVID-19 on Thursday, forcing their first game to be postponed after the All-Star break.

Those who contract mild illness after vaccination could also exhibit symptoms of so-called long-term COVID, said Priya Duggal, epidemiologist at Johns Hopkins, who was on appeal with Dowdy.

People who have caught COVID-19 are also likely to be protected from reinfection for at least a year, according to a study published last month. The researchers found that getting the vaccine after an infection increased the activity of the neutralizing antibodies needed to repel the virus by 50 times and prevented infection with variants.

“There are still unknowns about the extent and duration of protection against natural infections and the quality of protection against newer variants,” Grad said. “Even people who have had COVID-19 are still encouraged to get vaccinated. “

Although the vaccines appear to be effective against the current variants, if the virus gets out of hand anywhere in the world, new variants can emerge that could challenge immunity, Dowdy said.

“As long as the virus circulates, mutates in other countries, it will also be a threat to us,” he said.

What can be done?

To reverse the rise in infections, what is needed “is really to inject a sense of urgency into the equation,” Ostrosky said, recommending that people get vaccinated and start wearing face masks again. indoors when in public.

“If we don’t act now, we’re just going to find ourselves in the same situation we were in a year ago with closures, disruptions with deaths,” he said. “It’s very disheartening.”

Ostrosky said he believes there are still two types of people who refuse vaccination: those who remain very uninformed and those who need more assurance that they will not be harmed by the vaccines, which have now been administered to over 185 million Americans. “Access is really not the problem right now, it’s more reluctance,” he said.

Unfortunately, he said, the people most reluctant to get vaccinated are also the most reluctant to wear masks.

Los Angeles County announced on Thursday that it would reinstate a mask mandate for indoor public spaces.

Kullar said she wished the Centers for Disease Control and Prevention would wait longer before saying masks are not necessary for people who are fully vaccinated. Instead of urging them to be vaccinated, the CDC’s decision simply encouraged everyone, including the unvaccinated, to take off their masks, she said. “It confused the audience even more.”

She thinks people should continue to wear masks indoors in public places until at least 70% of the people in their community or county are vaccinated, “and if you’re immunocompromised, I won’t. would not remove your mask “.

The outdoors remain safe, she said, especially if people keep their distance from others.

The one thing that will remain most important in the battle against COVID-19, Ostrosky said, is for people to get vaccinated.

“We can do it,” he said. “We do not have time to lose.”

Contact Karen Weintraub at [email protected].

Patient health and safety coverage at USA TODAY is made possible in part by a grant from the Masimo Foundation for Ethics, Innovation and Competition in Healthcare. The Masimo Foundation does not provide editorial contributions.

This article originally appeared on USA TODAY: The fourth wave of COVID-19 has arrived. How big will it be? Too early to know.