Transposing a dataframe while unifying duplicates in a column

Question

I have a DataFrame that looks like the following:

index              group               Severity    count
0                  AA                      high        2
1                  AA                       low        2
2                  BB                      high        5
3                  BB                       low        1

I would like to obtain:

index              group                   high      low
0                  AA                         2        2
1                  BB                         5        1

I am not really interested in the index part, so it could as well be:

group                   high      low
AA                         2        2
BB                         5        1