It seems tempting to wait for screening test results, but since this is a 2- or 3-dose series that most adults need, we do not recommend missing an opportunity to vaccinate. Vaccination today helps protect a person who needs it. Even for specialists who work with patient groups with an increased likelihood of previous infection, such as people who use injection drugs, we encourage administering the first dose just after screening (at the same visit). If results show no further vaccination is needed then the vaccine series can be stopped at that point. If the results show further vaccination is needed, as it will with most people, then only one or two more doses will be needed to complete the series.