## Checklist

#### Is there any data?

Testing data is publicly available. (high confidence | DPC, ISS)

#### Do numbers refer to ‘performed tests’ or ‘individuals tested’?

In Italy (excluding Marche) “tamponi” (“swabs”) refers to “performed tests”: several patients are tested more than once. (high confidence | DPC, YT)

In Marche

• “tamponi” refers to “individuals tested” up to 13-04 (excluded); (high confidence | PM)
• “tamponi” refers to “performed tests” from 13-04 (included). (high confidence | PM1, PM2, IP)

National and regional data on “individuals tested” (“casi testati”) has been publicly available since 19-04. (high confidence | DPC, YT)

Patients who are recovered from COVID-19 are tested at least 3 times: 1 positive and 2 negative. (high confidence | DPC, YT)

“Guariti” (“recovered”) in the official data refers not only to those actually recovered (i.e. who tested negative twice), but to all those discharged from hospital. (high confidence | DPC, IP, IS24O, YT)

#### Are negative results included? Are pending results included?

In Italy “tamponi” include negative test results. (high confidence | DPC)

In Italy “tamponi” should include those that are pending results. (high confidence | DPC, PM)
Unfortunately this is not true for all regions:

• In Valle d’Aosta “tamponi” are divided as follows
• those analysed in-region exclude those that are pending results
• those analysed out-of-region include those that are pending results. (high confidence | PM)
• In Piemonte “tamponi” include those that are pending results. (high confidence | PM)
• Documentation for Liguria is not available yet.
• In Lombardia “tamponi” include those that are pending results. (high confidence | PM)
• Documentation for Trentino-Alto Adige is not available yet.
• In Veneto “tamponi” exclude those that are pending results. (high confidence | PM)
• Documentation for Friuli-Venezia Giulia is not available yet.
• In Emilia Romagna “tamponi” include those that are pending results. (high confidence | PM)
• In Toscana “tamponi” include those that are pending results. (high confidence | PM)
• In Umbria “tamponi” include those that are pending results. (high confidence | PM, UDPC)
• In Marche “tamponi” exclude those that are pending results. (high confidence | PM)
• Documentation for Lazio is not available yet.
• Documentation for Abruzzo is not available yet.
• Documentation for Molise is not available yet.
• In Campania “tamponi” exclude those that are pending results. (high confidence | PM)
• Documentation for Puglia is not available yet.
• In Basilicata “tamponi” include those that are pending results. (high confidence | PM)
• Documentation for Calabria is not available yet.
• Documentation for Sicilia is not available yet.
• In Sardegna “tamponi” exclude those that are pending results. (high confidence | PM)

#### Do the figures include all tests conducted in the country, or only some?

Figures reported by Italian authorities include all tests conducted in all working laboratories of the country. (medium-high confidence | MTP27-02, MTP09-03, MTP03-04)

#### Are all regions and laboratories within a country submitting data on the same basis?

The figures published at a given date attempt to include all tests conducted up to that date, but significant and variable delays are present: both from symptom onset to diagnosis ($$T_{s,d}$$) and from diagnosis to official notification ($$T_{d,n}$$). (medium-high confidence | ISS)

The median delay between the symptom onset and the date of diagnosis is

• 3 days for the period 20/02-29/02 (calculated on 1,609 cases);
• 5 days for the period 01/03-20/03 (37,060 cases);
• 7 days for the period 21/03-10/04 (27,637 cases);
• 6 days for the period 11/04-23/04 (6,299 cases). (high confidence | ISS)

In Italy the average delays are $$\langle T_{s,d} \rangle = 5.5 \text{ days }$$ and $$\langle T_{d,n} \rangle = 7 \text{ days }$$. (high confidence | ISS+FBK 1, ISS+FBK 2)

In Lombardy the delays are $$T_{s,d}= 7.3 \text{ days } (1,20)_{95\% \text{CI}}$$ and $$T_{d,n} = 3.6 \text{ days } (1,10)_{95\% \text{CI}}$$. (high confidence | AXV)

#### Are there any issues that affect the comparability of the data over time?

There have been significant changes over time in the ministerial testing protocol. (high confidence | ISS, MTP27-02, MTP09-03, MTP03-04, AXV)

#### What are the typical testing practices in the country?

Not all Italian regions follow the ministerial protocol of the central government, therefore there is significant regional heterogeneity in testing practices. (high confidence | IP, IP, IP)

Up to 20-03 we could identify 3 classes of testing practices described by the following pseudocode: consider two patients $$A$$ and $$B$$ living in the same house in the region $$R \in \{X, Y, Z\}$$ such that

• $$A$$ has no symptoms;
• $$B$$ suffers from symptoms compatible with COVID-19;
• $$X$$ respects the ministerial document dated 9-03 (e.g. Piedmont);
• $$Y$$ makes more tests than those recommended by the ministerial document dated 9-03 (e.g. Veneto)
• $$Z$$ makes fewer tests than those recommended by the ministerial document dated 9-03 (e.g. Lombardy).

If $$A$$ and $$B$$ live in $$X$$:

• ASL sends an ambulance team of health-workers who perform the test on him, but not to $$A$$ as he does not show any symptoms.
• $$A$$ ends up in isolation, since in contact with a person who is definitely infected.

If $$A$$ and $$B$$ live in $$Y$$:

• Test to $$B$$
• Test to $$A$$
• Test to the first and second neighbors (e.g. parents, friends, condominiums) in the hope of finding and isolating all the positives.

If $$A$$ and $$B$$ live in $$Z$$:

• No test to $$B$$ (unless $$B$$ needs hospital care)
• No test to $$A$$
• No isolation from $$A$$ because there is no evidence that $$B$$ is positive despite its symptoms.

#### Might any of the information above be lost in translation?

Many important documents released by official sources are translated in English. (high confidence | DPC, ISS, MDS)