A Single Heterologous Booster Vaccination Study of TAK-019 in Healthy Japanese Adults (COVID-19)

TAK-019 is a vaccine in development to protect people against Covid-19. The main aims of the study are to learn if TAK-019 can protect people from Covid-19 and to check for side effects from TAK-019 for participants who will receive TAK-019 as heterologous booster vaccination.

This study consists of two parts, main part and extension part. Firstly, participants who completed 2 doses primary vaccinations 6 to 12 months prior to the trial vaccination can take part in main study. At the first visit of main part of this study, the study doctor will check if each person can take part. Participants who can take part will receive an injection of TAK-019 as booster vaccination.

Participants will be asked to record their temperature and any medical problems in an electronic diary for up to 7 days after the injection. During the main part, participants will visit the clinic for regular check-ups, blood tests, and sometimes for nose swab samples. When all participants have attended a clinic visit 28 days after the injection, the study sponsor (Takeda) will check how many participants have made enough antibodies to protect them against Covid-19.

Participants who received the first single booster vaccination of TAK-019 in the main part and remained in study follow-up at least 5 months will be able to decide to take part in the extension part of this study. At the first visit of extension part of this study, the study doctor will check if each person can take part. Participants who can take part will receive an injection of TAK-019 as a second booster vaccination at the first visit of extension part.

The participants will stay in the main part of this study for up to 12 months after they have had their injection or up to the start of extension part. For participants who will take part in the extension part, they will stay in the extension part for up to 12 months from the start of extension part. During this time, the doctors will continue to collect blood samples to check immune response. Also, they will check if participants have any more side effects from TAK-019.


Eligibility Criteria:
Inclusion Criteria:

MAIN PART:

1. Healthy Japanese male and female adult participants aged \>= 20 years of age at the time of signing of informed consent.
2. Participant who completed 2 doses primary vaccinations with another specified mRNA vaccine which is available in Japan 6 to 12 months prior to the trial vaccination.

   EXTENSION PART:
3. Participants who received the first trial vaccination at least 5 months earlier and are currently enrolled in the Main Part (ie, not have withdrawn or discontinued early).

Exclusion Criteria:

MAIN PART:

1. Participants who received any other SARS-CoV-2 vaccine (except for the specified mRNA vaccine) or other experimental novel coronavirus vaccine prior to the trial.
2. Participant who received a booster vaccination (i.e. 3rd dose)
3. Participants who have close contact of anyone known to have COVID-19 within 14 days prior to the trial vaccination.
4. Participants who were tested positive for SARS-CoV-2 prior to the trial.
5. Participants who have traveled outside of Japan in the 30 days prior to the trial participation.
6. Participants with a clinically significant active infection or oral temperature \>= 38 degree Celsius within 3 days of the intended date of the first single booster vaccination.
7. Participants with body mass index (BMI) greater than or equal to 30 kg/m\^2 (BMI= weight in kg/ height in meters\^2)

   EXTENSION PART:
8. Participants with a clinically significant active infection or oral temperature \>=38 degree Celsius within 3 days of the intended date of the second single booster vaccination.