How to get the covid vaccine injected or not by id

To add to what Dave has said, how could you look up to see if anyone in the world has been vaccinated given an id, given two important details:
1) There is no global "People ID" which will uniquely identify a person in any system. It would probably make things a whole load simbler if there were ...
2) Access to any information on individuals is likely to be heavily restricted - and that includes vaccination status - because it will contain personal information. And local / global legislation generally provides severe penalties for releasing that without the persons consent: Google "GDPR" for one example.

If you are talking about your own database, then it's just a matter of issuing a parameterised SELECT query or similar (and being careful not to violate GDPR and other data protection legislation) but we can't tell you "do this" without knowing a lot more about your system and where / how the data is stored.
For SQL Server in C# it would be something like this:

using (SqlConnection con = new SqlConnection(strConnect))
    {
    con.Open();
    using (SqlCommand cmd = new SqlCommand("SELECT Date1stJab, Date2ndJab FROM Vaccinations WHERE ID = @ID", con))
        {
        cmd.Parameters.AddWithValue("@ID", myTextBox.Text);
        using (SqlDataReader reader = cmd.ExecuteReader())
            {
            while (reader.Read())
                {
                DateTime first = (DateTime) reader["Date1stJab"];
                DateTime second = (DateTime) reader["Date2ndJab"];
                ...
                }
            }
        }
    }