Un json così non lo avevo ancora disassemblato. Perciò questo è un tentativo (funzionate) da rivedere
codice:
Option Strict On
Imports l = libreria.ModuloWeb
Imports Newtonsoft.Json

Partial Class prove_a
    Inherits System.Web.UI.Page

    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        Dim wc As System.Net.WebClient = Nothing
        Try
            wc = New System.Net.WebClient()
            Dim url As String = "https://raw.githubusercontent.com/pcm-dpc/COVID-19/master/dati-json/dpc-covid19-ita-andamento-nazionale.json"
            Dim s As String = "{Propertys:" & wc.DownloadString(url) & "}"

            Dim r As Rootobject = If(Not String.IsNullOrWhiteSpace(s), JsonConvert.DeserializeObject(Of Rootobject)(s), New Rootobject())

            'stampo data e deceduti
            For Each p In r.Propertys
                PrintLn(Me.PlaceHolder1, p.deceduti, p.data.ToString)
            Next

        Catch ex As Exception
            Me.Label1.Text = l.exMessageErrorForLabel(ex)
        End Try
    End Sub




    Public Class Rootobject
        Public Property Propertys As List(Of Class1)
    End Class

    Public Class Class1
        Public Property data As Date
        Public Property stato As String
        Public Property ricoverati_con_sintomi As Integer
        Public Property terapia_intensiva As Integer
        Public Property totale_ospedalizzati As Integer
        Public Property isolamento_domiciliare As Integer
        Public Property totale_attualmente_positivi As Integer
        Public Property nuovi_attualmente_positivi As Integer
        Public Property dimessi_guariti As Integer
        Public Property deceduti As Integer
        Public Property totale_casi As Integer
        Public Property tamponi As Integer
        Public Property note_it As String
        Public Property note_en As String
    End Class

End Class