This study aimed to build a
consensus on recommendations of immunity requirements for vaccine-preventable diseases among healthcare and non-healthcare workers, including volunteers, at the Tokyo 2020 Olympic and Paralympic Games. We used a two-round Delphi method with a group of 17 Japanese medical doctors involved in vaccination or public health administration. We asked them to rank the importance of immunity to each vaccine-preventable disease as mandatory, recommended, considered if possible, or standard precautions only. The response rate was 88.2% (15/17) for the first questionnaire and 100% (17/17) for the second. All respondents considered that immunity to measles, rubella, varicella, mumps, and hepatitis B should be mandatory for healthcare workers, and 15 of 17 respondents considered that immunity to influenza should also be mandatory. Seven, three, two, and two respondents thought that immunity to pertussis, meningococcal disease, diphtheria, and tetanus should be mandatory, and ten, 11, seven, and seven thought it should be recommended. For non-healthcare workers, immunity to measles, rubella, and varicella was considered mandatory by 17, 15, and 15 respondents. Ten and eight respondents thought that immunity to mumps and influenza should be mandatory, and seven thought that it should be recommended. In conclusion, the
consensus was that immunity to measles, rubella, and varicella should be mandatory for both healthcare and non-healthcare workers. Immunity to mumps, hepatitis B, and influenza was also considered mandatory for healthcare workers. Further discussions may be needed to develop a
consensus on other vaccine-preventable diseases, especially if vaccination is not routine for adolescents or adults in Japan.