Figures & data
Figure 1. This study included individuals aged ≥16 years visiting participating hospitals or clinics with one or more of the following signs or symptoms: fever (≥37.5°C), cough, fatigue, shortness of breath, myalgia, sore throat, nasal congestion, headache, diarrhea, taste disorder, or olfactory dysfunction, and tested for SARS-CoV-2 in Japan between 1 January 2022, and 26 June 2022. Abbreviations: SARS-CoV-2, severe acute respiratory syndrome coronavirus 2; COVID-19, coronavirus disease 2019.
Table 1. Demographics and characteristics of test-positive cases and test-negative controls: VERSUS study, Japan, 1 January to 26 June 2022.
Figure 2. Vaccine effectiveness of messenger RNA COVID-19 vaccines against symptomatic SARS-CoV-2 infections among individuals aged 16 to 64 years and aged ≥65 years, VERSUS study, Japan, 1 January–26 June 2022. The analysis included test-positive cases with signs or symptoms that tested positive for SARS-CoV-2, and test-negative controls with signs or symptoms that tested negative for SARS-CoV-2. Vaccine effectiveness was adjusted for age, sex, underlying medical conditions, calendar week of test, history of contact with COVID-19 patients within 14 days, healthcare professional status, and medical facilities. The vaccination status was classified into three statuses based on the number of vaccine doses received before symptom onset and the number of days between the last vaccination date and symptom onset: no vaccination, individuals had received no vaccine dose before symptom onset; primary vaccination, individuals had received the second dose ≥14 days before symptom onset; and booster vaccination, individuals had received the third dose ≥14 days before symptom onset. Completion of vaccination was defined as 14 days after receiving the last vaccine. When evaluating vaccine effectiveness separated by days after vaccination, the number of days is shown from completion of vaccination. Abbreviation: VE, vaccine effectiveness.
Figure 3. Relative vaccine effectiveness of messenger RNA COVID-19 booster vaccination, compared with the primary vaccination against symptomatic SARS-CoV-2 infections among individuals aged 16 to 64 years and aged ≥65 years, VERSUS study, Japan, 1 January–26 June 2022. The analysis included test-positive cases with signs or symptoms and tested positive for SARS-CoV-2 and test-negative controls with signs or symptoms and tested negative for SARS-CoV-2. Vaccine effectiveness was adjusted for age, sex, underlying medical conditions, calendar week of test, history of contact with COVID-19 patients within the last 14 days, healthcare professional status, and medical facilities. The vaccination status was classified into two statuses based on the number of vaccine doses received before symptom onset and number of days between the last vaccination date and symptom onset: primary vaccination, individuals had received the second dose ≥14 days before symptom onset; and booster vaccination, individuals had received the third dose ≥14 days before symptom onset. Completion of vaccination was defined as 14 days after receiving the last vaccine. When evaluating vaccine effectiveness separated by days after vaccination, the number of days is shown from completion of vaccination. Abbreviation: VE, vaccine effectiveness.
Figure 4. Vaccine effectiveness of messenger RNA COVID-19 vaccines against symptomatic SARS-CoV-2 infections stratified by subgroups among individuals aged 16 to 64 years, VERSUS study, Japan, 1 January–26 June 2022. The analysis included test-positive cases with signs or symptoms and tested positive for SARS-CoV-2 and test-negative controls with signs or symptoms and tested negative for SARS-CoV-2. Vaccine effectiveness was adjusted for age, sex, underlying medical conditions, calendar week of test, history of contact with COVID-19 patients within the last 14 days, and medical facilities. The vaccination status was classified into three statuses based on the number of vaccine doses received before symptom onset and number of days between the last vaccination date and symptom onset: no vaccination, individuals had received no vaccine dose before symptom onset; primary vaccination, individuals had received one dose ≥14 days before symptom onset; and booster vaccination, individuals had received two doses ≥14 days before symptom onset. Completion of vaccination was defined as 14 days after receiving the last vaccine. When evaluating vaccine effectiveness separated by days after vaccination, the number of days is shown from completion of vaccination. Underlying medical conditions included chronic heart disease, chronic respiratory disease, obesity (body mass index ≥30 kg/m2), malignancy (including solid or hematological malignancy), diabetes, chronic kidney disease, receiving dialysis, liver cirrhosis, use of immunosuppressive medicines, and pregnancy. We assessed VE in two separate periods, as follows: (1) BA.1-dominant period defined as between 1 January 2022, and 13 March 2022, when more than 78% of the circulating variant was BA.1; and (2) BA.2-dominant period defined as between 11 April 2022, and 26 June 2022, when more than 80% was BA.2. Abbreviation: VE, vaccine effectiveness.
