TRACING THE CONTACTS OF
PEOPLE INFECTED WITH COVID-19:
THE HEALTH INSURANCE
ORGANISATION HIGHLY INVOLVED,
UNCERTAIN EFFECTIVENESS
Fiscal years 2020-2021 - update to September 2022
Flash Audit
December 2022
2
EXECUTIVE SUMMARY
Identification of contact persons at risk or contact tracing
Between 2020 and August 2022, 34.5 million cases of Covid-19 contamination
1
were
identified in France (excluding self-test results). More than 150,000 people died, of which
almost 126,400 died in hospital
2
.
Contact tracing, deployed from May 2020 after the first lockdown period
3
, is one of the
tools for combating this epidemic. It consists of contacting, by telephone, SMS or email, the
people who have tested positive so that they can identify the people with whom they have had
contact at risk, then contacting them, while preserving the anonymity of the positive people,
and using these exchanges to communicate prevention instructions (tests to detect
contamination for the contact people or recovery for those who have tested positive; isolation
while waiting for or following their results).
The involvement of the health insurance organisation in an
unprecedented, large-scale and evolving public health mission
In an emergency, the health insurance organisation
4
created a new information system,
set up departmental platforms of investigators, recruited thousands of fixed-term and then
permanent contract workers to stabilise the workforce and continuously adapted its system.
Since May 2020, the health insurance organisation has reached more than 32 million
people who tested positive and almost 22.7 million contact persons, first by telephone and then
mainly by SMS or email.
In total, expenditure on contact tracing, particularly on personnel, could exceed
€600
million over the three years 2020 to 2022.
Overall effectiveness uncertain
Without contact tracing, it is likely that contaminations would have been more numerous
or rapid and the impact on hospitals greater, but these impacts cannot be quantified in the
absence of scientific evaluation.
More than nine out of ten people who tested positive or were reported to the health
insurance organisation as contact cases were reached, and more than 90% of the positive
people reached were reached within 24 hours of the test result. In contrast, only 70-80% of
contacts were reached within 24 hours of being identified.
Above all, the health insurance organisation has only managed to identify a potentially
minority portion of the contact persons. On average, one out of every two people who tested
positive reported no contacts in 2020 and 2021. By increasing its workload, the epidemic
waves have led the health insurance organisation to lighten its procedures for tracing contact
cases. Given the impact of the 5
th
to 7
th
waves on the number of people to be contacted, the
1
Contaminations recorded in SiDep from March 2020 to August 2022. The Court
’
s investigation took into account
the results of the tests recorded in SiDep and, conversely, not the results of the self-tests which are not tracked
there.
2
Santé Publique France Data and Data.gouv.fr
3
The Court made initial observations on this system in its report on the application of social security financing laws
published in October 2021 (Chapter IV
“
Social security bodies in the health crisis, initial observations
”
).
4
Cai
sse nationale d’assurance maladie / Cnam
3
health insurance organisation used electronic means for most of the tracing procedures.
However, sending SMS to positive people to invite them to report their contacts on a website
results in fewer contact reports than telephone calls. In the first half of 2022, almost 90% of the
positive persons reported no contact.
In addition, the few elements of analysis available show partial compliance by the
positive persons and their contacts with the prevention instructions they received, which could
only have reduced the effectiveness of contact tracing.
A scheme on the verge of extinction, lessons to be learned
Vaccination has become the main instrument for fighting the epidemic, while contact
tracing now only records a small proportion of contacts (less than 0.5 on average per positive
person in July 2022, compared with almost 2.5 in November 2021).
The law of 30 July 2022 putting an end to the exceptional schemes created to combat
the Covid-19 epidemic means that this system will be discontinued on 31 January 2023, after
the new epidemic wave has begun and potentially during a new wave in winter. The number
of staff dedicated by the health insurance organisation to contact tracing has been drastically
reduced (350 FTEs of fixed-term and permanent contracts in September 2022, compared with
an average of 6,500 in 2021).
However, it seems essential that the tools, procedures and learning effects of contact
tracing be developed for the future. In the event of new large-scale epidemics or an increase
in the virulence of the Covid-19 epidemic (should the protection provided by the available
vaccines become insufficient), the public authorities should be able to rapidly activate an
operational and more effective system pending effective vaccination coverage.
The main findings of the survey
Contact tracing of at-risk contacts of persons who test positive is a prevention measure
for Covid-19 that has become secondary as a result of the increase in vaccination.
The health insurance organisation was heavily involved in this unprecedented and
large-scale public health mission and reached several tens of millions of positive people and
contacts within a short time.
However, it was only able to identify some of the contacts. The replacement of
telephone calls by SMS requests to report contacts on the internet has been accompanied
by a fall in the number of contacts reported. The effectiveness of contact tracing was also
affected by factors beyond the control of the health insurance organisation (non-compliance
with the prevention instructions given).
As contact tracing will cease at the end of January 2023, a scientific evaluation of its
impact on the Covid-19 contamination chains should be carried out in order to design a more
effective system in the event of new epidemics
.
4
RECOMMENDATION
Single recommendation:
on the basis of a scientific evaluation of the impact of contact tracing
on the Covid-19 contamination chains, design a crisis mechanism aimed at breaking these
chains and which can be activated and then deactivated rapidly in the event of new large-scale
epidemics (Ministry of Health and Prevention, SPF, Cnam).