PL/SQL calculates current date with past date with decimal output.

date.sql

(select round(round(months_between(sysdate,v_date),0)/12,1) from dual) as date_age

PatientUtil.vb

Public Class PatientUtil
    Public Shared Function FormatAge(ByVal date_age As String) As String
        Dim date_age_year As String
        Dim date_age_month As String
        Dim date_age_delimiter As Char = "."c
        Dim substrings() As String

        'First, get it:
        substrings = date_age.Split(date_age_delimiter)
        'Second turn decimal (2.40) into readable string (2 years 4 months)
        'begin by format year:
        date_age_year = substrings(0)
        If date_age_year = "1" Then
            date_age_year = "1 year "
        ElseIf date_age_year = "0" Then
            date_age_year = Nothing
        Else
            date_age_year = substrings(0) & " years "
        End If

        'next, format month
        If Not substrings.Count = 1 Then
            date_age_month = substrings(1)
            If date_age_month.Contains("0") Then
                If date_age_month = "10" Then
                    date_age_month = "10 months"
                Else
                    date_age_month = substrings(1).Substring(0, 1) & " months"
                End If
            End If

            If Not substrings(0) = "0" Then
                Return date_age_year & " " & vaccine_date_age_month
            Else
                Return date_age_month
            End If
        End If

        Return date_age_year
    End Function
End Class