NYC Phases Out Positivity Rate For COVID Decisions—Just As The CDC Says It’s Useful


Beginning subsequent week, New York Metropolis will not use COVID positivity as an indicator of the pandemic’s grip on the 5 boroughs, the mayor introduced. As an alternative, circumstances, vaccinations and hospitalizations will information the town’s coverage selections.

“It’s simply not going to be how we strategically make selections,” Mayor Invoice de Blasio stated Monday of the information level that judges what number of checks come again with an an infection.

The pivot comes after the Facilities for Illness Management and Prevention issued new masks steerage primarily based partly on positivity fee. The company now recommends that everybody put on face coverings indoors, no matter vaccination standing, in areas the place circumstances rise above 50 infections per 100,000–or if the positivity fee jumps above 8%.

As of August 2nd, group transmission is distinguished sufficient in all 5 boroughs and all however one New Jersey county to make common masking a good suggestion, in response to CDC information.

The mayor and metropolis Well being Commissioner Dr. Dave Chokshi cited widespread vaccination and low testing charges as a cause to cease asserting positivity fee, which is calculated by dividing the variety of constructive checks by the full variety of checks taken in a given day. Though genetic testing through PCR declined together with circumstances between April and early July, the seven-day fee has risen dramatically in current weeks—from simply over 22,000 on July fifth to greater than 33,000 on July thirtieth.

Certainly, day by day PCR testing this yr hasn’t fallen wherever close to the low factors witnessed in spring 2020, when the nation struggled to display folks for infections. And, in response to metropolis well being division information, sufficient checks are being finished to precisely gauge transmission in additional than 83% of New York Metropolis neighborhoods.

The variety of checks being finished does have an effect on the accuracy of the positivity fee information, notes Dr. Denis Nash, an epidemiology professor on the CUNY Graduate Faculty of Public Well being. However with testing on the rise and extensively out there, that alone isn’t a cause to desert the metric—particularly when so many individuals are unvaccinated.

“The positivity fee will not be one thing I might eliminate,” he stated. “I don’t discover the rationale that the mayor and different consultants gave very compelling.”

That’s as a result of unvaccinated individuals are extra more likely to catch the virus and get tested–making positivity an essential gauge of how the virus is circulating amongst those that are least protected.

And it’s higher to depend on extra metrics, moderately than fewer, when making an attempt to evaluate group transmission. The positivity fee, for instance, signifies whether or not an space is working out of sources to maintain monitor of asymptomatic circumstances. A distinct metric–called the efficient replica quantity or an infection progress rate–would clarify how briskly the outbreak is constructing.

“It’s at all times been problematic to depend on anyone indicator,” Nash stated. “All of those metrics are imperfect in a technique or one other. If you take a look at them suddenly, they have an inclination that will help you see one thing near what the true image is likely to be.”

The well being division will nonetheless publish positivity charges on its information web page, the mayor and metropolis well being commissioner stated. At the moment, their groups launch citywide in addition to neighborhood-level numbers.

The positivity reached a rolling common of three% citywide on July thirtieth, the very best it’s been since late April. Charges range extensively throughout the town—from simply over 1% in elements of Queens to just about 8% within the Annadale/Rossville and Charleston/Prince’s Bay/Woodrow neighborhoods of Staten Island.