Request to extend the shelf life of R21 to 18 months

Change of conduct/management of the trial: 1. Groups are now sub-divided with a new naming scheme for clarity in understanding and documentation during the trial. 2. Vaccination time point intervals have been shortened and windows have also been increased due to further scientific consideration of optimum dosing intervals. 3. Compensation amounts updated to reflect the new visit schedules. 4. Advertising materials have been updated 5. Collection of GP records has been clarified. 6. R21 storage details have been updated in the trial protocol following recommendations from the manufacturer. 7. Blood films are no longer required for diagnosis following validation of qPCR 8. Text has been added to the protocol clarifying university of oxford intellectual property terms. 9. R21 IB has been updated (reference safety information now refers exclusively to SARs, formulation and storage of R21 has been updated). 10. Consent form amended to a generic version that can be used at sites other than Oxford 11. Wording changed in PIS regarding malaria diagnosis from "two negative malaria tests" to "malaria tests showing a significant decrease in parasites" for increased clarity 12. To avoid the possibility of discrepancies: one original consent form will now be signed by volunteers and investigators, with this then being subsequently photocopied and provided to the volunteer, rather than two originals. 13. For harmonisation purposes, screening windows have now been shortened to 3 months from 6 months 14. The local safety committee chairman will be re-designated as the local safety monitor “LSM”. 15a. Various changes to visits have been made throughout the protocol. 17. Safety section of the protocol has been updated to remove reference to adverse events of special interest. We are collecting the usual AEs that we always collect in our vaccine trials at the Jenner institute and for the same duration of time.

Change in conduct of trial: 1. The window of vaccination 3 for Group 2a and 2b has been increased. It now has a -35 day window. This is because from recent research presented, showing better immunogenicity and efficacy with a delayed third vaccine dose, time points used by the 2 research groups have varied between 4.5 months and 7 months after first vaccination (NCT03906474). Therefore it is unknown when exactly the best time to give the third dose is. By extending this window and reducing the time between 2nd and 3rd dose, we are giving a wider range for the time he third dose can be given and falls in to the range of 4.5-7 months. This also helps facilitate timelines with CHMI. We have not changed the PIS to reflect this as no windows on vaccinations are mentioned in the PIS and also, at the time of screening, consent and enrolment, the volunteers were informed about this research and the possibility of the window on vaccination 3 changing. 2. In the procedures table, 'diary card completed' row has been amended so that in every group, this check is done 28 days post each vaccination. 3. In section 7.1.4, a correction has been made. There has been no change to dosing regimen. The groups mentioned for vaccination were Groups 1-3 when it should have been Groups 1-5. 4. In section 9.4.9, clarification if volunteer has extra clinical review, qPCR will be performed. This will be performed instead of thick film microscopy in view of qPCR now being a validated assay and our experience in other CHMI trials where qPCR has diagnosed malaria earlier than microscopy. 5. The diary given to volunteers post CHMI has now been converted to an electronic format. While the paper diary will still be there as a back-up, in the first instance, volunteers will be asked to record these details electronically now, similar to what they do post vaccinations.

Change in conduct of trial and change of PI: 1) In the last 3 CHMI trials conducted at the Jenner Institute (VAC 065a, VAC 065b and VAC 066), 1 control volunteer in each trial who underwent CHMI did not become infected with malaria. However, when looking at biting and infectivity records, these do not seem to differ from other volunteers who have undergone CHMI and have become infected. In view of this, we leave open now the option to increase the number of volunteers, should suitable volunteers be available, from 6 to 8 subjects in Groups 6 and 7 to gain more power in showing adequate malaria infection in control volunteers to be able to make suitable comparisons to vaccination groups when determining efficacy. 2) We have increased the group number sizes for Groups 4b and 5. These groups are testing the safety and immunogenicity of delayed, fractional dosing and with Group 4b, a higher dose of R21 compared to the rest of the trial. We feel it would be beneficial to have larger numbers in these groups to gain more data on these dosing regimes to help us decide if these regimes are justified to proceed into efficacy trials against CHMI. 3) The PI at NIHR Imperial College has changed from Prof David Lewis to Dr Katrina Pollock as Prof Lewis is retiring.

1. Group 1: optional booster vaccine approximately 60 weeks after the first vaccination with immunology follow up. During RTS,S/AS01B efficacy trials, increased efficacy was seen following a fourth vaccine. Given this finding, we plan to assess the immunological effect of a booster vaccine. 2. Group 2a and 3a: For volunteers demonstrating sterile protection in the first challenge a) optional booster vaccine (rationale as above) AND/OR b) long term immunology follow up to assess durability of immunogenicity. As per previous protocol, all protected volunteers will be invited back for a re-challenge. The booster vaccination will be timed to occur prior to the re-challenge. Volunteers will have the choice if they want a booster vaccination or not or if they just want to have the re-challenge. 3. Group 4 and 5: optional CHMI To test efficacy (protection from P. falciparum) of delayed dose regimes and compare efficacy between regimes. The window on this third, delayed fractional dose has been increased. This is because from the unpublished studies but recent research presented, showing better immunogenicity and efficacy with a delayed third vaccine dose, time points used by the 2 research groups have varied between 4.5 months and 7 months after first vaccination (NCT03906474). Therefore, it is unknown when exactly the best time to give the third dose is. By extending this window and reducing the time between 2nd and 3rd dose, we are giving a wider range for the time the third dose can be given, and falls in to the range of 4-9 months. 4. Clarification of challenge arrangements 5.Timing of re-challenge and booster vaccinations for protected volunteers in Groups 2a and 3a

1. Additional measures taking place in view of COVID-19. These include social distancing practises in clinical areas/use of PPE/adhering to PHE guidance for isolation rules and testing/what will happen in the event of a fever post vaccination or malaria challenge. 2. Windows on vaccinations for all groups have been increased. These include booster vaccinations for Groups 1/2/3, or 3rd vaccination for Groups 4/5, and all follow-up visits. This is in view of participants potentially self- isolating or if they are unable to travel to us. Telephone assessments will still take place over this period to ensure safety. • When ECGs will be performed for Groups 4/5 have been clarified in these tables also as these are needed prior to malaria challenge and can occur at any vaccination visit. • COVID-19 swab necessary at the day before the challenge to ensure that the participant does not have COVID-19 when we are giving them malaria. 3. Change of malaria diagnosis endpoint. This is to ensure diagnosis as early as possible to reduce number of clinic visits. 4. Change in follow up time post malaria challenge. This again is reduced to ensure there are less clinic visits. This will still be safe as we are diagnosing malaria at a lower parasite threshold and everyone is treated with antimalarials at the end of follow-up, regardless of if they are protected or not. 5. Clarification of treatment of malaria so Riamet and Malarone are both first-line options. 6. Compensation and blood volumes adjusted to reflect these changes. 7. Reporting of positive SARS-CoV-2 test results, as required by law.• In this case, the result and personal data (including volunteer name, contact details, and postcode) will be shared in a secure manner with Public Health England for referral to the NHS Test and Trace system.