Ruminations

The (Elusive) Goal: Achieving Herd Immunity

"We found that test positivity rates were higher in lower income areas [and] among the Black population."
"Further studies are needed to understand how populations are at risk of becoming infected [and to better understand the socioeconomic determinants of infection]."
"[We hope the] information out of New York can help our colleagues to identify populations that are at risk in this country [as rates of infection climb in several areas of the country]."
"[We at Northwell Health hope to better understand the] genetic predispositions of patients and characteristics of the virus, in order to identify better ways to tailor treatment."
"The story is still being written in terms of the COVID contagion. Time is of the essence in trying to stay ahead of the virus."
Dr. Jim Crawford, chair, Department of Pathology, Long Island Jewish Medical Center and North Shore University Hospital

Stephane Labossiere, right, with the Mayor's Office of Immigrant Affairs, hands out masks and printed information about free COVID-19 testing in Brooklyn being offered by NYC Health + Hospitals, Wednesday, July 8, 2020, in New York. Mark Lennihan/AP

New findings arising out of a study that Dr.Crawford and his research colleagues undertook based on antibody tests at a clinic in the Corona neighbourhood of Queens suggest that specific areas of New York have achieved close to a 70 percent immunity rate to COVID-19; a "stunning" revelation leading to the belief that the residents involved may very well be in a protected state from a second wave of the novel coronavirus.

Health care company City-MD made the results available to local media, that a higher antibody rate than anywhere else in the world has been established, the data released publicly. The Italian province of Bergamo, also hard hit by the global pandemic had a 57 percent immunity to COVID, and the site of Austria's largest coronavirus outbreak at the Alpine ski resort Ischgl, reported a 47 percent rate.

But it is in some boroughs of New York city, emergency doctors related, that the rates reflect what the clinical presentations have informed, with an emphasis on areas of the city of lower income and high minority populations. Those very areas where experts theorized would be hardest hit, due not only to the density of the population, but because of poverty and the limitations imposed on people in such circumstances.

An earlier study, however, seemed to indicate that such dense areas of inner cities were able to manage surprisingly well, the lockdown ensuring that people stayed where they were, in a limited geographic range, venturing out when absolutely required, and realizing in the end, a lower infection rate than parts of the outer city where populations are unable to walk short distances to a destination, must drive and drive further to access shopping and appointments becoming more susceptible to infection.

The figures of 68 percent antibodies at Queens and 56 at another clinic in Jackson Heights of positive tests affirm an approach to the high antibody rate required to establish herd immunity. And it seems clear to some from New York City's testing program that herd immunity has been achieved by some such communities, raising the prospect that other jurisdictions abroad that have been hard hit with COVID, may also experience herd immunity, where a 70 percent infection rate arming people with antibodies passes the test.

Not everyone is in agreement however. Virologists feel the results may not be representative of the general population since testing had taken place at urgent care centres; warning insufficient data exists to definitively conclude that herd immunity has been achieved, given that little is known as well how rigorously testing was carried out, and whether false positives occurred.

Just five percent of the population tested positive in Spain where the largest and most meticulous antibody study had been carried out in a survey of 60,000 people across the nation, and not with a focus on any single area. Among the hardest-hit cities in the world, New York recorded 222,000 cases and close to 23,000 deaths up to the present.

About 314,000 tests were administered by CityMD, up to June 26, with 26 percent of the tests positive. A study using antibody tests to determine what proportion of the population was infected from early March to the present woould require a study with a different focus. Antibody research found roughly 20% of the New York City population acquired infections, nowhere near the 60% experts agree would confer herd immunity.