Study of Gamma PN3 in the Elderly

Inclusion Criteria:

1. Male or female volunteers aged 70 years and over at Screening.

2. In stable good general health as determined by the outcome of medical history,physical examination, and clinical judgement by the Investigator. Chronic stablenon-inflammatory conditions such as hypertension, hyperlipidemia, well-controlledtype 2 diabetes, stable asthma, controlled psychiatric conditions such as anxiety ordepression, stable ischemic heart disease with heart failure not greater than NYHAGrade 1 and 2 are permitted, as determined by the Investigator.

3. Willing and able to give voluntary written informed consent before screeningassessments commence.

4. Vital signs within the following ranges (inclusive):

• Body temperature 35.5 to 37.7°C

• Heart rate 50 to 100 beats per minute although atrial fibrillation is allowed.

• Respiratory rate 12 to 22 breaths per minute

• Systolic blood pressure 90 to 160 mmHg

• Diastolic blood pressure 50 to 95 mmHg

5. 12-lead ECG parameters within the following ranges:

• QTcB & QTcF - males ≤450 msec. females ≤470 msec

• PR 100 to 240 msec inclusive

• Heart rate (HR) 50 to 100 beats per minute (bpm) inclusive; atrial fibrillationis allowed.

6. Willing and able to communicate with the Investigator and study team and understandsthe requirements of the study.

7. Willing and able to undertake the study visits and all assessments, includingpossessing a suitable device and access to the internet for using the web-basedelectronic diary (e.g., smartphone, tablet, or computer) and able to use the devicefor this purpose.

8. Vaccinated against severe acute respiratory syndrome corona virus 2 (SARS-CoV-2;COVID-19) with a minimum of a prime and boost vaccinations.

Exclusion Criteria:

1. History of a previous Pneumovax 23® vaccination in last 12 months. 2. Historyof a previous Prevenar 13® or Prevenar 20® vaccination in last 12 months.

2. Positive serology blood test for human immunodeficiency virus (HIV) antibodies,hepatitis B virus (HBV) surface antigen or Hepatitis C virus (HCV) antibodies.Positive serology to Hepatitis C due to previous successfully treated infectionwith negative polymerase chain reaction (PCR) is not exclusionary.

3. Infectious disease including but not limited to COVID-19 and influenza within 30 days before Screening and any time between Screening and Day 1 first dose,as this may confound immune response to study vaccine.

4. Liver function tests (including aspartate aminotransferase [AST], alanineaminotransferase [ALT], bilirubin) >1.5 upper limit of normal (ULN).

5. Clinically significant abnormalities in laboratory tests (biochemistry,haematology), physical examination, or 12-lead ECG during the Screening periodthat, in the opinion of the Investigator, would affect immune response tovaccination and/or ability to fully participate in the study and/or not be inthe individual's best interest to participate in the study. One re-test perabnormality is permitted.

6. Participation in another clinical study of any investigational or licensedproduct (including investigational COVID-19 vaccines, drugs, medical devices)or medical procedure within 4 weeks from last study visit before screening.

7. Plan to have a vaccine during the study period including COVID-19 booster. 9.Have had a live vaccine within three months of the first dose of study productor any other vaccine (including any COVID-19 vaccine) within 28 days of thefirst dose of study product.

Examples of live vaccines include, but are not limited to the following: measles, mumps, rubella, chicken pox/zoster (Zostavax; Shingrix is allowed), monkeypox, yellow fever, rabies, Bacillus Calmette-Guérin, and typhoid (oral) vaccines. Seasonal influenza vaccines for injection are generally killed virus vaccines and are permitted if administered at least 28 days before the first dose of study treatment and not during the enrollment or the study period. However, intranasal influenza vaccines are live attenuated vaccines and are not permitted within three months of first dose.

10. Have received blood or blood-derived products in the last three months beforescreening, which might interfere with assessment of the immune response.

11. Known or suspected congenital or acquired immunodeficiency; or receipt ofimmunosuppressive therapy such as anti-cancer chemotherapy or radiation therapywithin the last six months before screening; or long-term systemic corticosteroidtherapy (prednisone at a dose of 5mg daily or equivalent for more than twoconsecutive weeks within the last month before screening, depot or intraarticularsteroids within 3 months before screening).

12. A systemic inflammatory condition such as rheumatoid arthritis or inflammatory boweldisease.

13. Any medical condition requiring immunosuppressive therapy. 14. History of severeallergic reaction e.g., severe cutaneous adverse reaction or anaphylaxis to anymedicinal product or to any of the study treatments, including excipients.

14. Current alcohol abuse (> 21 U/week for men and 14 U/week for women), substancedependence including nicotine/tobacco smoking (defined as more than 5 cigarettes ortobacco/nicotine equivalent per day; smoking or vaping will not be permitted whileat the study unit), any use of illicit drugs or other addiction which mightinterfere with the ability to comply with study procedures in the opinion of theInvestigator; positive drugs of abuse screen (tricyclic antidepressants, opioids,and benzodiazepines are not exclusionary if prescribed by a physician and consistentwith medical history) or positive alcohol breath test at Screening or pre-dose. Onere-test permitted for drugs of abuse screen where justified (e.g., false positivesuspected).

15. Clinically significant chronic illness that, in the opinion of the Investigator, isat a stage where it might interfere with study conduct or completion. Examplesinclude congestive heart failure NHYA Grade 3 or 4, COAD with breathlessnessinterfering with daily activities; severe psychiatric conditions, poorly controlledasthma or diabetes 17. Any chronic medical condition e.g., asthma, gout, which islikely to need systemic corticosteroid therapy during the study.

16. Renal impairment requiring dialysis 19. Identified as a site employee of theInvestigator or study center, with direct involvement in the proposed study or otherstudies under the direction of that Investigator or study center, as well as familymembers (i.e., immediate, husband, wife or de facto and their children, adopted ornatural) of the site employees or the Investigator.

17. Poor venous access making scheduled blood sampling likely to be unsuccessful