Just as Covid-19 cases keep rising in 17 states, holiday revelers crammed together without masks

Some Americans took warnings from health officials very seriously — wearing masks while in public, keeping their distance from strangers or celebrating the holiday weekend at home.

So 50% of antibody tests might be wrong, CDC says

The serologic tests, which are used to determine whether people have been infected in the past with Covid-19, might be wrong up to half the time.

“In a population where the prevalence is 5%, a test with 90% sensitivity and 95% specificity will yield a positive predictive value of 49%. In other words, less than half of those testing positive will truly have antibodies,” the CDC says.

They are not accurate enough to use to make important policy choices, the CDC says.

“Serologic test results should not be used to make decisions about returning persons to the workplace,” it says. It should not also factor into decisions at correctional facilities, K-12 schools and college residence halls, the CDC says.

It is best to use tests with high specificity, the CDC adds.

‘The disease can jump out at any time’

What used to be typical summer pastimes are now potential breeding grounds for coronavirus.

In Arkansas, one of the few states that never enacted stay-at-home orders, Gov. Asa Hutchinson said the state seemed to be experiencing a “second peak.”

Despite the warning, crowds gathered over the weekend in Lake Hamilton, where Karen Lee said many people decided to forgo masks.

And officials from the World Health Organization say those who ignore measures such as social distancing are at risk of seeing a resurgence of the coronavirus.

“We cannot make assumptions that just because the disease is on the way down now that it’s going to keep going down,” said Dr. Mike Ryan, executive director of WHO’s Health Emergencies Programme.

“We need to be also cognizant of the fact that the disease can jump up at any time.”

A hallmark of coronaviruses “is its ability to amplify in certain settings, its ability to cause transmission or super spreading events,” said Maria Van Kerkhove, the WHO’s technical lead for Covid-19 response.

“And we are seeing in a number of situations in these closed settings (that) when the virus has an opportunity, it can transmit readily,” she said.

Authorities are cracking down on rules

To avoid resurgences, state and local officials are trying to enforce restrictions in place across much of the country.

Health officials in St. Louis County, Missouri, issued a travel advisory after videos surfaced from Lake of the Ozarks, where hundreds crowded a pool party.

“This reckless behavior endangers countless people and risks setting us back substantially from the progress we have made in slowing the spread of COVID-19,” County Executive Dr. Sam Page said.

Those who were in the area should self-quarantine for two weeks if they didn’t practice social distancing, county officials said.

In Houston, authorities will enforce capacity limits after the city received hundreds of complaints over the weekend of bars and restaurants that were violating those limits.

In Rhode Island, police officers and park rangers were stationed at East Matunuck and Scarborough state beaches to ensure residents were wearing masks and following social distancing restrictions.

There will no longer be lifeguards on duty, parking will be limited, and access to bathrooms, changing rooms and concessions is no longer allowed, WPRI reported.

2 months after its containment zone, New Rochelle reopens

New Rochelle — once the epicenter of New York’s coronavirus outbreak — was starting to reopen Tuesday, Mayor Noam Bramson said.

“The resumption of construction and retail pickup in Phase I will be a welcome boost to our local economy, and New Rochelle is already making plans to accelerate our recovery through both business and individual assistance,” Bramson said in a written statement.

“But it is premature to let down our guard. All of us must continue to act responsibly, practice physical distancing, use face coverings, and follow other guidelines intended to safeguard our health at both home and work.”