The phantom herd immunity to covid-19

When most of a population is immune to an infectious disease either by natural infection or by vaccination, this provides indirect protection — or herd immunity — to those who are not immune to the disease.

A positive antibody response does not necessarily mean that there is immunity but nevertheless it may give a first indication how many individuals may have had contact with a virus. Be aware of several infodemic websites on seroprevalence. Also note that most information is distributed by news agencies, press offices and preprints only bypassing usual standards in science. Unfortunately also most tests have not been properly standardized.


countrydateNrepresentativeantibody prevalence %methodLink
Wuhan, China2Apr201.401no10?journal
Robbio, Italy6Apr202.000?no?13.5?link to Ref 24 by Bendavid not working
Telluride, USA8Apr20986?0.8?newspaper
Santa Clara, USA17Apr203.330no (Facebook)1.5Premier Biotech, Minneapolismedrxiv
Netherlands15Apr207.361no (plasma donors)3.1Wantai Biological PharmacyNIH
Los Angeles, USA20Ap20863yes?4.1?press release
Trieste, Italy22Apr20727no (clinic staff)17.2Wantai SARS-CoV-2 Ab Rapid Testmedrxiv
Brevard, USA24Apr201000no?1.0?newspaper
Miami, USA14Apr201.800yes4.4-7.9?press release
Scotland, GB17Apr201.000no (blood donors)1.0neutralisation assaymedrxiv
Chelsea, USA17Apr20200no (passengers)32?newspaper via Science
New York, USA27Apr207.500??15.0?newspaper
Denmark28Apr209,496no (blood donors)1.7Livzon Diagnostics IgM/IgGmedrxiv
GermanyMay20 (weekly)1.342yes1.0?RKI
Iran1May20551yes22VivaDiag COVID‐19 VivaCheckmedrxiv
Barcelona, Spain2May20578no (healthcare worker)9.3Luminex / Krammermedrxiv
Gangelt, Germany4May20919no (hotspot)14.1Euroimmun?UK Bonn
Padova, Italy1May20133no (health care worker)5.3Chemiluminescencemedrxiv
San Miguel County, USA1May205.455?0.5UB?website
Philadelphia, USA9May20237no (patients)5.9own ELISA / Florian Krammerresearchsquare
Boise, USA7May204.856no (self selected)1.8Abbott SARS-CoV-2 IgGjournal
Kobe, Japan5May201.000no (outpatients)3.3RC-NC002, KURABOmedrxiv
Wake Forest, USA8May20676no (former patients)2.2?newspaper
Lausanne, Schweiz6May20 (weekly)1.335yes3.1, 6.1, 9.7Euroimmunmedrxiv
Brazil10May204.188yes0.05, 0.13Wondfo Biotech medrxiv<7a>
Singapore12May2032.000no (workers in dorms)??newspaper
Berlin, Germany13May205.000 / 7.500no (Charité staff)2.3, 0.3?Ärzteblatt
Spain15May2060.000yes (?)5.0?Reuters
Cambridge, UK15May201.032no (health care worker)3.0own protocolmedrxiv
Hannover, Germany18May20217no (health care worker)1.0Euroimmunmedrxiv
Stockhom, Sweden19May201.104yes?7.3?newspaper
Birmingham, UK22May20554no (health care worker=24.4high-sensitivity ELISA developed in-housemedrxiv


There is  preprint that lists some studies that I could not locate so far.

Prevalences should NOT be compared for methodological reasons.

No idea from where the NYT data originate.