Studies on COVID-19 Lethality

Reposted from Swiss Policy Research

Updated: July 2021
Published: May 2020
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[Editor: the following is a bit sciency but is well worth the study.]

Overview

1) Antibody studies ⇓ 2) Immunology ⇓ 3) Median age of death ⇓ 4) Hospitalizations ⇓ 5) Nursing homes ⇓ 6) Overall mortality ⇓ 7) Influenza comparison ⇓ 8) Seroprevalence per country ⇓

1) Antibody studies

The covid infection fatality rate (IFR) depends on demographics (age and risk structure), public policies (e.g. protection of care homes), and medical treatment quality. In most Western countries, the median age of covid deaths is 80+ years and about 50% of deaths occurred in care homes (s.b.)

For comparison, the IFR of seasonal influenza, against which prior immunity and vaccines exist, is about 0.05% to 0.1%; the IFR of epidemic and medium pandemic influenza, such as in 1936, 1951, 1957 and 1968, is about 0.3%; the IFR of the 1918 pandemic influenza was about 2%. (Source)

In terms of covid-19 IFRs, an important difference exists between places with and without a partial or total collapse of local health and elderly care, and between the early and late pandemic phase. In the following table, NNH refers to the non-nursing home population (see section 5).

Country	Published	Population	IFR (%)	Source
Global
Low estimate	Oct. 2020	51 locations Below 70 years	0.20¹ 0.04¹	Ioannidis
High estimate	Sept. 2020	24 locations	0.68	GMK
Africa
Kenya	July 2020	National	<0.1	Uyoga
Malawi	Aug. 2020	National	<0.1	Grace
Asia
India	July 2020	Delhi Mumbai	0.14 0.23	India
Indonesia	Jan. 2021	National	0.10	UOI
Iran	May 2020	Guilan province	0.12	Shakiba
Europe
Austria	June 2020	Ischgl (NNH)	0.26	von Laer
Belgium	Dec. 2020	General population Incl. care homes 40 to 49 years	0.58 1.47 0.05	Hens
Denmark	April 2020	Blood donors (<70y)	0.08	Erikstrup
England	Aug. 2020 (low est.)	General (MCT) General (ONS)	0.30 0.49	CEBM
Aug. 2020 (high est.)	General population Incl. care homes 45 to 64 years Below 44 years	0.90 1.43 0.50 0.03	Ward
Germany	May 2020 Nov. 2020	Heinsberg (NNH) Munich (NNH)	0.36 0.48²	Streeck LMU
Iceland	Sept. 2020	General population Below 70 years	0.30 0.10	NEJM
Italy (Lombardy)	Aug. 2020	Below 70 years Below 50 years 80+, first phase 80+, second ph.	0.43 <0.01 30.40 8.10	Poletti
Spain (early phase)	Aug. 2020	Confirmed covid Excess deaths Below 50 years Below 40 years	0.82 1.07 <0.10 <0.03	Pollan
Sweden	June 2020	Stockholm (NNH) Stockholm <70y	0.35³ 0.09	FOHM
Switzerland	July 2020 Aug. 2020	Geneva (NNH) Zurich (NNH)	0.324 0.304	Perez Aguzzi
Latin America
Brazil	Sept. 2020 Sept. 2020	Maranhao Manaus	0.17 0.28	da Silva Buss
Colombia	June 2021	National	0.27	Guzman
United States
Indiana	Sept. 2020	General population	0.26	AIM
Santa Clara	April 2020	General population	0.175	Bendavid
Miami-Dade	April 2020	General population	0.185	Miami
Los Angeles	April 2020	General population	0.205	Sood
New York City (early phase)	June 2020	Overall	0.70	Stadlbauer
June 2020	Confirmed Probable 25 to 44 y. <25 years	1.10 1.45 0.12 0.01	Yang

1) Median values; 2) 0.76% including nursing homes (36% of deaths); 3) 0.58% including Stockholm nursing homes (about 40% of deaths, see page 23); 4) 0.64% and 0.60% including nursing homes;  5) These US studies may underestimate the true IFR, as they were done early during an accelerating pandemic.

The above chart shows the very significant difference between IFRs in the entire population (including nursing homes, left) and in the non-nursing home population (right) at the example of Belgium. The IFR in 85-year-old nursing home patients (about 20%) is almost 20 times higher than the IFR in people of the same age outside of nursing homes (about 1%).

2) Immunological aspects

Immunological research indicates that serological antibody studies, which measure antibodies in the blood (mostly IgG), may detect only about 50% to 80% of all coronavirus infections, depending on the sensitivity of the assay, the timing of the test, and the population tested.

This is because some people neutralize the coronavirus primarily with their mucosal (IgA) or cellular (T-cells) immune system and develop only mild symptoms or no symptoms. These people may develop no measurable IgG antibodies or may show them only for a certain time.

The following chart shows that six months after an infection, the sensitivity of antibody assays in non-hospitalized patients ranged from 98% (e.g. Roche) to just 30% (e.g. the widely used Abbott assay). Thus, some antibody studies may underestimate infections and overestimate IFRs.

3) Median age of Covid-19 deaths per country

Half of all deaths were below, half were above the median age.

Country	Median age	Source
Australia	82 years	DOH
Austria	82 years	EMS
Belgium	86 years	IBS
Brazil	70 years	MDX
Canada	86 years	HCSC
England	82 years	NHS
France	84 years	SPF
Germany	83 years	RKI
Italy	82 years	ISS
South Africa	62 years	SAC
Spain	82 years	MDS
Sweden	84 years	FOHM
Switzerland	86 years	BAG
USA	78 years	CDC

The following chart shows the percentage of covid deaths per age group in various countries. While in many European countries, up to 90% of deaths affect people older than 70 years of age, in many Latin American countries, up to a third of deaths affect people younger than 60 years of age.

4) Hospitalization rate

Initial estimates based on Chinese data assumed a very high 20% hospitalization rate, which led to the strategy of ‘flattening the curve’ to avoid overburdening hospitals. However, population-based antibody studies (see above) have since shown that actual hospitalization rates are closer to 2%, which is comparable to hospitalization rates for influenza (1 to 2%).

The US CDC found that Covid-19 hospitalization rates for people aged 65 and over are “within ranges of influenza hospitalization rates”, with rates somewhat higher for people aged 18 to 64, but “much lower” (compared to influenza) for people under 18.

In hotspots like New York City, the hospitalization rate based on antibody studies was about 2.5% (20% or 1.7 million people with antibodies and 43,000 hospitalizations by early May 2020). The lower-than-expected hospitalization rate may explain why many covid-19 ‘field hospitals’, e.g. in the US and the UK, remained largely unused.

5) Percentage of Covid-19 deaths in care homes

In most Western countries, deaths in care homes account for 30% to 60% of all covid deaths. In Canada and some US states, care homes account for up to 80% of all covid-related deaths. In Sweden, deaths in nursing homes and nursing apartments account for 70% of all deaths.

6) Overall mortality

By the end of March 2021, there were close to 3 million covid deaths in close to 8 billion people. At a global infection attack rate of 10% to 30%, this results in an average global covid lethality (IFR) of 0.1% to 0.35% and a global covid mortality of about 0.035%. By comparison, the 1918 flu pandemic had a global mortality of about 2.3% (40 million deaths in 1.8 billion people).

See also: Covid-19 Mortality: An Overview (March 2021)

A comparison between the number of coronavirus deaths predicted by the influential model of Imperial College London (no measures or moderate measures) and the actual number of deaths in Sweden indicates that the model significantly overestimated the impact of the epidemic:

7) Coronavirus vs. influenza pandemics

The following chart shows US mortality by age in previous pandemic years compared to 2020 US excess mortality, which consisted primarily (>75%) of confirmed and suspected covid-19 deaths, according to the CDC. To learn more about this comparison, please read this article.

8) Antibody seroprevalence per country

Percentage of people with measurable antibodies to the new coronavirus.

Country	Date	Region	Antibodies	Source
Europe
Belgium	June 2020	National Brussels	7% 12%	Herzog
Denmark	Nov. 2020 Aug. 2020	National Copenhagen	3.9% 3.2%	SSI SSI
England	July 2020	National North West London	6% 12% 17%	PHE
France	Mar. 2021	National Paris region	21% 37%	PFR
Germany	Mar. 2021 Dec. 2020 June 2020 April 2020	National National National Gangelt	15% 5% <2% 15%	RKI
Hungary	June 2020	National Budapest	0.7% 0.8%	Merkely
Iceland	July 2020	National	0.9%	NEJM
Ireland	Aug. 2020	National Dublin	1.7% 3.1%	HSPC
Italy	July 2020	National Bergamo Lombardy Sicily	2.5% 38% 7.5% 0.3%	ISTAT
Netherlands	July 2020	National South	4% 16%	RIVM
Poland	May 2021	Wrocław (IgG) Wrocław (IgA)	35% 52%	Budziar
Russia	June 2020	National Moscow Petersburg	14% 20% 5.7%	TMT TMT EUSP
Spain	Dec. 2020 Dec. 2020	National Madrid	10% 19%	Franco
Sweden	May 2020 Nov. 2020	National Stockholm	5% 31%	FOHM DNSE
Switzerland	Jan. 2021 Nov. 2020 Jan. 2021 June 2021	Zurich Ticino Geneva Geneva	11% 16% 21% 33%	BAG UGE
Ukraine	Jan. 2021	National	43%	LNMU
Americas
Brazil	Aug. 2020 Feb. 2021	Maranhao Sao Paulo	40% 25%	Silva SPS
Canada	June 2020	National Quebec Ottawa Vancouver	0.7% 2.2% 1.3% 0.6%	BCA
USA	Mar. 2021 Mar. 2021	National New York Oregon S. Dakota	35% 35% 11% 48%	CDC C19P
Asia
China	Apr. 2020 May 2020	Wuhan Hubei Rest Wuhan	4.5% 0.5% <0.1% 2.4%	Lancet CMI
India	July 2021 June 2021 Jan. 2021	National Delhi National	68% 60% 22%	ICMR Misra NCDC
Indonesia	Jan. 2021 Mar. 2021	National National	15% 45%	Govt. DKI
Iran	July 2020	National Qom Rasht	17.1% 58.5% 72.6%	Lancet
Japan	July 2020	Tokyo	1.2%	Nawa
Saudi Arabia	Aug. 2020 Nov. 2020	National National	10% 20%	Alharbi
South Korea	Oct. 2020	National	0.6%	Lee
Africa
Congo	July 2020	Brazzaville	20%	IJID
Kenya	June 2020	National Nairobi	5.2% 8.3%	Uyoga
Nigeria	Oct. 2020	Lagos	23%	NCDC
South Africa	Jan. 2021	National	50%	MDX

See also

• Facts about Covid-19
• Covid Mortality Overview
• Covid vs. the flu, revisited

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