GET request data doesn't update

I'm trying to retrieve data from an API but my variable doesn't update even if I set it as nothing before the GET request.

The data of the variable update only if I close Excel and re-open it.

Is there any explanation for it? I've been scratching my head for so long.

Here is the code

Sub getJsonResult()
    Dim objRequestt As Object
    Dim strUrl As String
    Dim blnAsync As Boolean
    Dim strUrlXBTUSD As String
    Dim strResponse As String
    Dim jsonText As String
    Dim jsonObject As Object, item As Object
    Dim i As Integer

    'setting up the variable to 0 or nothing

    strUrlXBTUSD = ""
    strResponsee = ""
    jsonText = ""
    i = 0
 blnAsync = False
 Set item = Nothing
 Set jsonObject = Nothing
 Set objRequestt = Nothing
 Set objRequestt = CreateObject("MSXML2.XMLHTTP")
    strUrlXBTUSD = "https://www.bitmex.com/api/v1/orderBook/L2?symbol=XBTUSD&depth=3"
    blnAsync = True


    'Starting the GET request

    ThisWorkbook.Activate
    With objRequestt
        .Open "GET", strUrlXBTUSD, blnAsync
        .SetRequestHeader "Content-Type", "application/json"
        .send
        strResponse = .responseText 'here the response is always the same except if i Close Excel
           Debug.Print strResponsee
    End With
End Sub

At the end "strResponse" is always the same even after several F5 refresh. I can see that the data are no longer accurate on a web browser. I'd like the VBA program to get accurate data and refresh without closing Excel.

How to do that?