Pharmacotherapeutic group: Vaccine, COVID-19 vaccines, ATC code: J07BN01
Mechanism of action
Spikevax (elasomeran) and Spikevax LP.8.1 (mRNA-1273.251) contain mRNA encapsulated in lipid nanoparticles.
The mRNA encodes for the full-length SARS-CoV-2 spike protein modified with 2 proline substitutions within the heptad repeat 1 domain (S-2P) to stabilise the spike protein into a prefusion conformation. After intramuscular injection, cells at the injection site and the draining lymph nodes take up the lipid nanoparticle, effectively delivering the mRNA sequence into cells for translation into viral protein. The delivered mRNA does not enter the cellular nucleus or interact with the genome, is non-replicating, and is expressed transiently mainly by dendritic cells and subcapsular sinus macrophages. The expressed, membrane-bound spike protein of SARS-CoV-2 is then recognised by immune cells as a foreign antigen. This elicits both T-cell and B-cell responses to generate neutralising antibodies, which may contribute to protection against COVID-19.
Clinical efficacy of Spikevax (original)
In adults
The adult study was a randomised, placebo-controlled, observer-blind Phase 3 clinical study (NCT04470427) that excluded individuals who were immunocompromised or had received immunosuppressants within 6 months, as well as participants who were pregnant, or with a known history of SARS‑CoV-2 infection. Participants with stable HIV disease were not excluded. Influenza vaccines could be administered 14 days before or 14 days after any dose of Spikevax (original). Participants were also required to observe a minimum interval of 3 months after receipt of blood/plasma products or immunoglobulins prior to the study in order to receive either placebo or Spikevax (original).
A total of 30,351 subjects were followed for a median of 92 days (range: 1‑122) for the development of COVID-19 disease.
The primary efficacy analysis population (referred to as the Per Protocol Set or PPS), included 28,207 subjects who received either Spikevax (original) (n=14,134) or placebo (n=14,073) and had a negative baseline SARS-CoV-2 status.
The PPS study population included 47.4% female, 52.6% male, 79.5% White, 9.7% African American, 4.6% Asian, and 6.2% other. 19.7% of participants identified as Hispanic or Latino. The median age of subjects was 53 years (range 18-94). A dosing window of –7 to +14 days for administration of the second dose (scheduled at day 29) was allowed for inclusion in the PPS. 98% of vaccine recipients received the second dose 25 days to 35 days after dose 1 (corresponding to -3 to +7 days around the interval of 28 days).
COVID-19 cases were confirmed by Reverse Transcriptase Polymerase Chain Reaction (RT PCR) and by a Clinical Adjudication Committee. Vaccine efficacy overall and by key age groups are presented in Table 4.
Table 4. Vaccine Efficacy Analysis: confirmed COVID-19# regardless of severity starting 14 days after the 2nd dose – Per-Protocol Set
| Age Group (Years) | Spikevax (original) | Placebo | % Vaccine Efficacy (95% CI)* |
| Subjects N | COVID-19 Cases n | Incidence Rate of COVID-19 per 1,000 Person-Years | Subjects N | COVID-19 Cases n | Incidence Rate of COVID-19 per 1,000 Person-Years |
| Overall (≥18) | 14,134 | 11 | 3.328 | 14,073 | 185 | 56.510 | 94.1 (89.3, 96.8)** |
| 18 to <65 | 10,551 | 7 | 2.875 | 10,521 | 156 | 64.625 | 95.6 (90.6, 97.9) |
| ≥65 | 3,583 | 4 | 4.595 | 3,552 | 29 | 33.728 | 86.4 (61.4, 95.2) |
| ≥65 to <75 | 2,953 | 4 | 5.586 | 2,864 | 22 | 31.744 | 82.4% (48.9, 93.9) |
| ≥75 | 630 | 0 | 0 | 688 | 7 | 41.968 | 100% (NE, 100) |
#COVID-19: symptomatic COVID-19 requiring positive RT-PCR result and at least 2 systemic symptoms or 1 respiratory symptom. Cases starting 14 days after the 2nd dose.
*Vaccine efficacy and 95% confidence interval (CI) from the stratified Cox proportional hazard model
** CI not adjusted for multiplicity. Multiplicity adjusted statistical analyses were carried out in an interim analysis based on less COVID-19 cases, not reported here.
Among all subjects in the PPS, no cases of severe COVID-19 were reported in the vaccine group compared with 30 of 185 (16%) cases reported in the placebo group. Of the 30 participants with severe disease, 9 were hospitalised, 2 of which were admitted to an intensive care unit. The majority of the remaining severe cases fulfilled only the oxygen saturation (SpO2) criterion for severe disease (≤ 93% on room air).
The vaccine efficacy of Spikevax (original) to prevent COVID-19, regardless of prior SARS-CoV-2 infection (determined by baseline serology and nasopharyngeal swab sample testing) from 14 days after Dose 2 was 93.6% (95% CI: 88.6, 96.5%).
Additionally, subgroup analyses of the primary efficacy endpoint showed similar efficacy point estimates across genders, ethnic groups, and participants with medical comorbidities associated with high risk of severe COVID-19.
The level of protection gained after dose 1 was assessed in a post-hoc analysis in the mITT Set. In the interval 14 days after dose 1 to dose 2, there were 35 cases of COVID-19 on placebo and only 2 in the vaccine group. This indicates that the vaccine may provide some level of protection from 14 days after the first dose and before receiving dose 2. For optimal protection, two doses should be administered one month apart.
In adolescents 12 through 17 years of age
The adolescent study is a Phase 2/3 randomised, placebo-controlled, observer‑blind clinical study (NCT04649151) to evaluate the safety, reactogenicity, and efficacy of Spikevax (original) in adolescents 12 to 17 years of age. Participants with a known history of SARS-CoV-2 infection were excluded from the study. A total of 3,732 participants were randomised 2:1 to receive 2 doses of Spikevax (original) or saline placebo 1 month apart.
A secondary efficacy analysis was performed in 3,181 participants who received 2 doses of either Spikevax (original) (n=2,139) or placebo (n=1,042) and had a negative baseline SARS-CoV-2 status in the Per Protocol Set. Between participants who received Spikevax (original) and those who received placebo, there were no notable differences in demographics or pre-existing medical conditions.
COVID-19 was defined as symptomatic COVID-19 requiring positive RT‑PCR result and at least 2 systemic symptoms or 1 respiratory symptom. Cases starting 14 days after the second dose: there were zero symptomatic COVID-19 cases in the Spikevax (original) group and 4 symptomatic COVID‑19 cases in the placebo group.
In children 6 years through 11 years of age
The paediatric study is a Phase 2/3 randomised, placebo-controlled, observer-blind, clinical trial to evaluate the safety, reactogenicity, and efficacy of Spikevax (original) in children ages 6 years through 11 years in the United States and Canada (NCT04796896). Participants with a known history of SARS‑CoV-2 infection were excluded from the study. A total of 4,011 participants were randomised 3:1 to receive 2 doses of Spikevax (original) or saline placebo 1 month apart.
A secondary efficacy analysis evaluating confirmed COVID-19 cases accrued up to the data cutoff date of 10 November 2021 was performed in 3,497 participants who received two doses (0.25 mL at 0 and 1 month) of either Spikevax (original) (n=2,644) or placebo (n=853) and had a negative baseline SARS-CoV-2 status in the Per Protocol Set. Between participants who received Spikevax (original) and those who received placebo, there were no notable differences in demographics.
COVID-19 was defined as symptomatic COVID-19 requiring positive RT‑PCR result and at least 2 systemic symptoms or 1 respiratory symptom. Cases starting 14 days after the second dose.
There were three COVID-19 cases (0.1%) in the Spikevax (original) group and four COVID-19 cases (0.5%) in the placebo group.
In children 6 months through 5 years of age
A Phase 2/3 study was conducted to evaluate the safety, tolerability, reactogenicity, and efficacy of Spikevax in healthy children 6 months through 11 years of age. The study enrolled children in 3 age groups: 6 years through 11 years; 2 years through 5 years; and 6 months through 23 months.
A descriptive efficacy analysis evaluating confirmed COVID-19 cases accrued up to the data cutoff date of 21 February 2022 was performed in 5,476 participants 6 months through 5 years of age who received two doses (at 0 and 1 month) of either Spikevax (n=4,105) or placebo (n=1,371) and had a negative baseline SARS-CoV-2 status (referred to as the Per Protocol Set for Efficacy). Between participants who received Spikevax and those who received placebo, there were no notable differences in demographics.
The median length of follow-up for efficacy post-Dose 2 was 71 days for participants 2 years through 5 years of age and 68 days for participants 6 months through 23 months of age.
Vaccine efficacy in this study was observed during the period when the B.1.1.529 (Omicron) variant was the predominant variant in circulation.
Vaccine efficacy (VE) in Part 2 for the Per Protocol Set for Efficacy for COVID-19 cases 14 days or more after dose 2 using the “COVID-19 P301 case definition” (i.e., the definition employed in the pivotal adult efficacy study) was 46.4% (95% CI: 19.8, 63.8) for children 2 years through 5 years of age and 31.5% (95% CI: -27.7, 62.0) for children 6 months through 23 months of age.
Immunogenicity of Spikevax (original) after primary immunisation
In adolescents 12 through 17 years of age
A non-inferiority analysis evaluating SARS-CoV-2 50% neutralising titres and seroresponse rates 28 days after Dose 2 was conducted in the Per-Protocol immunogenicity subsets of adolescents aged 12 through 17 (n=340) in the adolescent study and in participants aged 18 through 25 (n=296) in the adult study. Subjects had no immunologic or virologic evidence of prior SARS‑CoV-2 infection at baseline. The geometric mean ratio (GMR) of the neutralising antibody titres in adolescents 12 to 17 years of age compared to the 18- to 25-year-olds was 1.08 (95% CI: 0.94, 1.24). The difference in seroresponse rate was 0.2% (95% CI: -1.8, 2.4). Non‑inferiority criteria (lower bound of the 95% CI for GMR > 0.67 and lower bound of the 95% of the seroresponse rate difference > -10%) were met.
In children 6 years through 11 years of age
An analysis evaluating SARS-CoV-2 50% neutralising titres and seroresponse rates 28 days after Dose 2 was conducted in a subset of children aged 6 years through 11 years (n=319) in the paediatric study and in participants aged 18 through 25 years (n=295) in the adult study. Subjects had no immunologic or virologic evidence of prior SARS-CoV-2 infection at baseline. The GMR of the neutralising antibody titres in children 6 through 11 years of age compared to the 18- to 25-year-olds was 1.239 (95% CI: 1.072, 1.432). The difference in seroresponse rate was 0.1% (95% CI: -1.9, 2.1). Non‑inferiority criteria (lower bound of the 95% CI for GMR > 0.67 and lower bound of the 95% CI of the seroresponse rate difference > -10%) were met.
In children 6 months through 5 years of age
For children aged 2 years through 5 years of age, comparison of Day 57 nAb responses in the per‑protocol immunogenicity subset (n = 264; 25 micrograms) to those of young adults (n = 295; 100 micrograms) demonstrated a GMR of 1.014 (95% CI: 0.881, 1.167), meeting the noninferiority success criteria (i.e., lower bound of the 95% CI for GMR ≥ 0.67; point estimate ≥ 0.8). The geometric mean fold rise (GMFR) from baseline to Day 57 for these children was 183.3 (95% CI: 164.03, 204.91). The difference in seroresponse rates (SRR) between the children and young adults was ‑0.4% (95% CI: ‑2.7%, 1.5%), also meeting the noninferiority success criteria (lower bound of the 95% CI of the SRR difference > ‑10%).
For infants and toddlers from 6 months through 23 months of age, comparison of Day 57 nAb responses in the per‑protocol immunogenicity subset (n = 230; 25 micrograms) to those of young adults (n = 295; 100 micrograms) demonstrated a GMR of 1.280 (95% CI: 1.115, 1.470), meeting the noninferiority success criteria (i.e., lower bound of the 95% CI for GMR ≥ 0.67; point estimate ≥ 0.8). The difference in SRR rates between the infants/toddlers and young adults was 0.7% (95% CI: -1.0%, 2.5%), also meeting the noninferiority success criteria (lower bound of the 95% CI of the seroresponse rate difference > ‑10%).
Accordingly, the pre-specified success criteria for the primary immunogenicity objective were met for both age groups, allowing efficacy of 25 micrograms to be inferred in both children 2 years through 5 years and infants and toddlers aged 6 months through 23 months (Table 5).
Table 5. Summary of geometric mean concentration ratio and seroresponse rate – comparison of individuals 6 months through 5 years of age to participants 18 years through 25 years of age – per-protocol immunogenicity set
| | 6 months through 23 months n=230 | 18 years through 25 years n=291 | 6 months through 23 months/ 18 years through 25 years |
| Assay | Time point | GMC (95% CI)* | GMC (95% CI)* | GMC ratio (95% CI)a |
| SARS-CoV-2 neutralisation assayc | 28 days after Dose 2 | 1,780.7 (1,606.4, 1,973.8) | 1,390.8 (1,269.1, 1,524.2) | 1.3 (1.1, 1.5) |
| Seroresponse % (95% CI)d | Seroresponse % (95% CI)d | Difference in seroresponse rate % (95% CI)e |
| 100 (98.4, 100) | 99.3 (97.5, 99.9) | 0.7 (-1.0, 2.5) |
| | 2 years through 5 years n=264 | 18 years through 25 years n=291 | 2 years through 5 years/ 18 years through 25 years |
| Assay | Time point | GMC (95% CI)* | GMC (95% CI)* | GMC Ratio (95% CI)a |
| SARS-CoV-2 neutralisation assayc | 28 days after Dose 2 | 1,410.0 (1 273.8, 1 560.8) | 1,390.8 (1 262.5, 1 532.1) | 1.0 (0.9, 1.2) |
| Seroresponse % (95% CI)d | Seroresponse % (95% CI)d | Difference in seroresponse rate % (95% CI)e |
| 98.9 (96.7, 99.8) | 99.3 (97.5, 99.9) | -0.4 (-2.7, 1.5) |
GMC = Geometric mean concentration
n = number of participants with non-missing data at baseline and at Day 57
* Antibody values reported as below the lower limit of quantification (LLOQ) are replaced by 0.5 x LLOQ. Values greater than the upper limit of quantification (ULOQ) are replaced by the ULOQ if actual values are not available.
a The log-transformed antibody levels are analysed using an analysis of covariance (ANCOVA) model with the group variable (participants 6 months through 5 years of age and young adults) as fixed effect. The resulted LS means, difference of LS means, and 95% CI are back transformed to the original scale for presentation.
b Noninferiority is declared if the lower bound of the 2-sided 95% CI for the GMC ratio is greater than 0.67, with a point estimate of >0.8 and the lower bound of the 2-sided 95% CI for difference in seroresponse rate is greater than -10%, with a point estimate of >-5%.
c Final geometric mean antibody concentrations (GMC) in AU/mL were determined using SARS-CoV-2 microneutralisation assay.
d Seroresponse due to vaccination specific to SARS-CoV-2 RVP neutralizing antibody concentration at a subject level is defined in protocol as a change from below LLOQ to equal or above 4 x LLOQ, or at least a 4-fold rise if baseline is equal to or above LLOQ. Seroresponse 95% CI is calculated using the Clopper-Pearson method.
e Difference in seroresponse rate 95% CI is calculated using the Miettinen-Nurminen (score) confidence limits.
Immunogenicity of Spikevax (original) after a booster dose (0.25 mL, 50 micrograms)
In adults
The safety, reactogenicity, and immunogenicity of a booster dose of Spikevax (original) are evaluated in an ongoing Phase 2, randomised, observer-blind, placebo-controlled, dose-confirmation study in participants 18 years of age and older (NCT04405076). In this study, 198 participants received two doses (0.5 mL, 100 micrograms 1 month apart) of the Spikevax (original) vaccine as primary series. In an open‑label phase, 149 of those participants (Per‑Protocol Set) received a single booster dose (0.25 mL, 50 micrograms) at least 6 months after receiving the second dose in the primary series. A single booster dose (0.25 mL, 50 micrograms) was shown to result in a geometric mean fold rise (GMFR) of 12.99 (95% CI: 11.04, 15.29) in neutralising antibodies from pre-booster compared to 28 days after the booster dose. The GMFR in neutralising antibodies was 1.53 (95% CI: 1.32, 1.77) when compared 28 days post dose 2 (primary series) to 28 days after the booster dose.
In adolescents 12 years through 17 years of age
The primary immunogenicity objective of the booster phase of this study was to infer efficacy of the booster dose in participants 12 years through 17 years of age by comparing post‑booster immune responses (Day 29) to those obtained post-dose 2 of the primary series (Day 57) in young adults (18 to 25 years of age) in the adult study. Efficacy of the 50 microgram Spikevax booster dose is inferred if post-booster dose immune responses (nAb geometric mean concentration [GMC] and seroresponse rate [SRR]) meet pre-specified noninferiority criteria (for both GMC and SRR) compared to those measured following completion of the 100 microgram Spikevax primary series among a subset of young adults (18 to 25 years) in the pivotal adult efficacy study.
In an open-label phase of this study, participants 12 years through 17 years of age received a single booster dose at least 5 months after completion of the primary series (two doses 1 month apart). The primary immunogenicity analysis population included 257 booster dose participants in this study and a random subset of 295 participants from the young adult study (ages ≥18 to ≤25 years) who previously completed a primary vaccination series of two doses 1 month apart of Spikevax. Both groups of participants included in the analysis population had no serologic or virologic evidence of SARS‑CoV‑2 infection prior to the first primary series dose and prior to the booster dose, respectively.
The GMR of the adolescent booster dose Day 29 GMC compared with young adults: Day 57 GMR was 5.1 (95% CI: 4.5, 5.8), meeting the noninferiority criteria (i.e., lower bound of the 95% CI >0.667 (1/1.5); point estimate ≥0.8); the SRR difference was 0.7% (95% CI: ‑0.8, 2.4), meeting the noninferiority criteria (lower bound of the 95% of the SRR difference >‑10%).
In the 257 participants, pre-booster (booster dose-Day 1) nAb GMC was 400.4 (95% CI: 370.0, 433.4); on BD-Day 29, the GMC was 7172.0 (95% CI: 6610.4, 7781.4). Post-booster booster dose‑Day 29 GMC increased approximately 18‑fold from pre-booster GMC, demonstrating the potency of the booster dose to adolescents. The SRR was 100% (95% CI: 98.6, 100.0).
The pre-specified success criteria for the primary immunogenicity objective were met, thus enabling the inference of vaccine efficacy from the adult study.
In children 6 years through 11 years of age
The primary immunogenicity objective of the booster phase of this study is to infer efficacy of the booster dose in participants 6 years through 11 years of age by comparing post-booster dose immune responses (Day 29) to those obtained post dose 2 of the primary series (Day 57) in young adults (18 years to 25 years of age) in that study, where 93% efficacy was demonstrated. Efficacy of the 25 microgram Spikevax booster dose is inferred if post-booster dose immune responses (neutralising antibody [nAb] geometric mean concentration [GMC] and seroresponse rate [SRR]) meet pre-specified non‑inferiority criteria (for both GMC and SRR) compared to those measured following completion of the 100 microgram Spikevax primary series among a subset of young adults (18 years to 25 years) in the pivotal adult efficacy trial.
In an open-label phase of this study, participants 6 years through 11 years of age received a single booster dose at least 6 months after completion of the primary series (two doses 1 month apart). The primary immunogenicity analysis population included 95 booster dose participants 6 years through 11 years of age and a random subset of 295 participants from the young adult study who received two doses 1 month apart of Spikevax. Both groups of participants included in the analysis population had no serologic or virologic evidence of SARS-CoV-2 infection prior to the first primary series dose and prior to the booster dose, respectively.
In the 95 participants, on booster dose-Day 29, the GMC was 5,847.5 (95% CI: 4,999.6, 6,839.1). The SRR was 100% (95% CI: 95.9, 100.0). Serum nAb levels for children 6 years through 11 years in the per‑protocol immunogenicity subset with pre-booster SARS-CoV-2 negative status and the comparison with those from young adults (18 years to 25 years of age) were studied. The GMR of booster dose Day 29 GMC compared to young adults Day 57 GMC was 4.2 (95% CI: 3.5, 5.0), meeting the noninferiority criteria (i.e., lower bound of the 95% CI > 0.667); the SRR difference was 0.7% (95% CI: -3.5, 2.4), meeting the noninferiority criteria (lower bound of the 95% of the SRR difference >-10%).
The pre-specified success criteria for the primary immunogenicity objective were met, thus enabling the inference of booster dose vaccine efficacy. The brisk recall response evident within 4 weeks of booster dosing is evidence of the robust priming induced by the Spikevax primary series.
Available data in children 12 weeks to 6 months of age
The safety and immunogenicity of Spikevax bivalent Original/Omicron BA.1 were evaluated in children 12 weeks to 6 months of age in Study P206. During the dose-finding part of the study, two dose levels (5 mcg and 10 mcg) evaluated as a 2-dose regimen were generally well tolerated but did not lead to a substantial immune response.
Other immunogenicity results with Spikevax (original)
Immunogenicity of a booster dose of Spikevax (original) following primary vaccination with another authorised COVID-19 vaccine in adults
Safety and immunogenicity of a heterologous booster with Spikevax (original) were studied in an investigator-initiated trial with 154 participants. The minimum time interval between primary series using a vector‑based or RNA‑based COVID-19 vaccine and booster injection with Spikevax (original) was 12 weeks (range: 12 weeks to 20.9 weeks). The dose used for boosting in this study was 100 micrograms. Neutralising antibody titres as measured by a pseudovirus neutralisation assay were assessed on Day 1 prior to administration and at Day 15 and Day 29 after the booster dose. A booster response was demonstrated regardless of primary vaccination.
Only short-term immunogenicity data are available; long-term protection and immunological memory are currently unknown.
Safety and immunogenicity of seven COVID-19 vaccines as a third dose (booster) in the UK
COV-BOOST is a multicentre, randomised Phase 2 investigator-initiated trial of third dose booster vaccination against COVID-19 with a subgroup to investigate detailed immunology. Participants were adults aged 30 years or older, in good physical health (mild to moderate well-controlled co-morbidities were permitted), who had received two doses of either Pfizer–BioNTech or Oxford–AstraZeneca (first dose in December 2020, January 2021 or February 2021), and were at least 84 days post second dose by the time of enrolment. Spikevax (original) boosted antibody and neutralising responses and was well tolerated regardless of the prime series. The dose used for boosting in this study was 100 micrograms. Neutralising antibody titres as measured by a pseudovirus neutralisation assay were assessed on Day 28 after the booster dose.
Immunogenicity in solid organ transplant recipients
The safety, reactogenicity, and immunogenicity of Spikevax (original) were evaluated in a two‑part Phase 3b open‑label study in adult solid organ transplant (SOT) recipients, including kidney and liver transplants (mRNA‑1273-P304). A 100 microgram (0.5 mL) dose was administered, which was the dose authorised at the time of study conduct.
In Part A, 128 SOT recipients received a third dose of Spikevax (original). In Part B, 159 SOT recipients received a booster dose at least 4 months after the last dose.
Immunogenicity in the study was assessed by measurement of neutralising antibodies against pseudovirus expressing the ancestral SARS-CoV-2 (D614G) strain at 1 month after Dose 2, Dose 3, booster dose and up to 12 months from the last dose in Part A, and up to 6 months from booster dose in Part B.
Three doses of Spikevax (original) induced enhanced neutralising antibody titres compared to pre‑dose 1 and post-dose 2. A higher proportion of SOT participants who had received three doses achieved seroresponse compared to participants who had received two doses. The neutralising antibody levels observed in SOT liver participants who had received three doses was comparable to the post-dose 2 responses observed in the immunocompetent, baseline SARS‑CoV‑2‑negative adult participants. The neutralising antibody responses continued to be numerically lower post-dose 3 in SOT kidney participants compared to SOT liver participants. The neutralising levels observed one month after Dose 3 persisted through six months with antibody levels maintained at 26‑fold higher and seroresponse rate at 67% compared to baseline.
A fourth (booster) dose of Spikevax (original) enhanced neutralising antibody response in SOT participants compared to post-dose 3, regardless of the previous vaccines received [mRNA-1273 (Moderna), BNT162b2 or any mRNA-containing combination]; however, SOT kidney participants had numerically lower neutralising antibody responses compared to SOT liver participants.
Elderly population
Spikevax (original) was assessed in individuals 6 months of age and older, including 3,768 subjects 65 years of age and older. The efficacy of Spikevax (original) was consistent between elderly (≥65 years) and younger adult subjects (18-64 years). Spikevax bivalent Original/Omicron BA.4-5 was assessed in 105 individuals ≥65 years of age (P205 Part H, safety analysis set).
Paediatric population
The licensing authority has deferred the obligation to submit the results of studies with Spikevax (original) and Spikevax LP.8.1 in one or more subsets of the paediatric population in prevention of COVID-19 (see section 4.2 for information on paediatric use).