Counting days for a given value without considering previous value

Hi, Anonymous 
You need to create a index column in query editor first

Then you can try  to create calculated columns as below:

color flag = 
VAR value1 =
    'COVID'[TRANSMISSIBILIDADE]
RETURN
    SWITCH (
        TRUE (),
        value1 > 1.5, "red",
        value1 >= 1
            && value1 <= 1.5, "orange",
        value1 < 1, "green"
    )

ChangedStatue = 
VAR pre =
    CALCULATE (
        VALUES ( COVID[color flag] ),
        FILTER ( ALL ( COVID ), 'COVID'[Index] = EARLIER ( COVID[Index] ) - 1 )
    )
RETURN
    IF ( ISBLANK ( pre ) || pre = 'COVID'[color flag],"unchanged","changed" )

Counting days = 
VAR _max =
    CALCULATE (
        MAX ( 'COVID'[Index] ),
        FILTER (
            'COVID',
            'COVID'[Index] <= EARLIER ( 'COVID'[Index] )
                && 'COVID'[ChangedStatue] = "changed"
        )
    )
RETURN
    IF ( ISBLANK ( _max ), 'COVID'[Index], 'COVID'[Index] - _max + 1 )

The result will show as below:

For more details,please check the attached file.

Best Regards,
Community Support Team _ Eason
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