Living Evidence - COVID-19 vaccines

Living evidence tables provide high level summaries of key studies and evidence on a particular topic, and links to sources. They are reviewed regularly and updated as new evidence and information is published.

There are four main types of vaccines and over 200 candidate vaccines in development. This table includes information on vaccines that have published phase 3 trial data in the peer reviewed literature and are provisionally approved by the Australian Government Therapeutic Goods Administration (TGA). It focuses on information related to efficacy, safety and rollout.

Regular checks are conducted for new content and any updates are highlighted. All highlights are removed each Monday.

  Comirnaty (Pfizer/BioNTech) BNT162b2Vaxzevria (Oxford/AstraZeneca) AZD1222Spikevax (Moderna) mRNA-1273 Johnson & Johnson Ad26.COV2.SNovavax NVX-CoV2373

Phase 3 trial publication

The New England Journal of Medicine (1)

The New England Journal of Medicine (2)

The Lancet (3)

The Lancet (4)

The New England Journal of Medicine

The New England Journal of Medicine

The New England Journal of Medicine

Vaccine type

mRNA (nucleic acid)

Viral vector

mRNA (nucleic acid)

Viral vector

Protein subunit
Dosing schedule from phase 3 trial

Two 30µg doses;

Dose interval 21 days

Two doses (5x1010viral particles);

Dose interval 28 days

Two 100µg doses;

Dose interval 28 days

One dose (5x1010 viral particles)

Two 5µg doses;

Dose interval 21 days

Efficacy - various endpoints

     

SARS-CoV-2 infection

14 to 20 days after Dose 1: 46%*
≥7 days after Dose 2: 92%* (2)

55.7%* (3)

54.1%* (4)

89.6%*

Not yet available

Not yet available

Asymptomatic infection

14 to 20 days after Dose 1: 29% (estimated)*

≥7 days after Dose 2: 90% (estimated)* (2)

LD/SD (initial half dose) 58.9% /SD/SD (full dose) recipients 3.8%
Total combined 27.3%*ꝉ (3)

COV002 UK study participants only: LD/SD 49.3%* / SD/SD 2.0%*
Total combined 22.2%* (4)

Not yet available

At day 71 days: 65.5%* Not yet available

Severe COVID-19

88.9% after Dose 1* (1)

14 to 20 days after Dose 1: 62%*
≥7 days after Dose 2: 92%* (2)

For hospitalisation:
14 to 20 days after Dose 1: 74%*
≥7 days after Dose 2: 87%* (2)

100%*ⱶ (3)

100% (US Phase 3 trial; 2 Doses administered 4 weeks apart)^

100%*

≥14 days after dose: 76.7%

≥28 days after dose: 85.4%

For hospitalisation:
≥14 days after dose: 93.1%*
≥28 days after dose: 100%*

100%*ⱶ (No hospitalizations or cases of severe infection were reported among the 10 cases in the vaccine group)

Mortality

14 to 20 days after Dose 1: 72% (estimated)* (2)

Not yet available

Not yet available

≥28 days after dose: 82.8%, with protection sustained through at least 6 months after administration.

Not yet available

Transmissionⱡ

Reduction in PCR positivity in contacts of index cases who received 2 doses versus non-vaccinated: adjusted rates ratio 0.32 for Alpha and 0.5 for Delta

Reduction in PCR positivity in contacts of index cases who received 2 doses versus non-vaccinated: adjusted rates ratio 0.48 for Alpha and 0.76 for Delta

Not yet available

Not yet available

Not yet available
Effectiveness ('real world' data)

Symptomatic/infection

The CDC reports low rate of new infections in vaccinated people (approx. 5800 of 77 million).^

Multiple studies show 73% to 97% effectiveness 7 days after Dose 2 (general population and healthcare workers).

0.35% to 0.46% of fully vaccinated people had breakthrough infections.

VE for infection: 18-49yr: Up to 93.6%. 50-64yr: Up to 95.3%. >65yr: Up to 91.9%. Immunosuppressed: 71%.

Asymptomatic

Multiple studies show 90% to 92% effectiveness 7 days after Dose 2.

Hospitalisation

Multiple studies show 71% to 97% effectiveness.^

At the 15–21 day period after the second dose, VE is 98.6% for severe/critical disease. As low as 0.09% of vaccinated people are hospitalised.

VE for hospitalisation: 18-49yr: up to 96.4%. 50-64yr: Up to 95.8%. >65yr: Up to 95%.

Mortality

Multiple studies show 85% to 98.7% effectiveness.^ mRNA vaccines 64.2% effective for partially vaccinated individuals.^

At the 15–21 day period after the second dose, VE is 97.7% for deaths.

Transmission

Effectiveness against transmission has been shown to be up to 88.5%.

Risk of household transmission 49% lower if index cases vaccinated ≥21 days prior to testing positive (compared to no vaccination).^

Vaccination reduced susceptibility to infection by 89.4% and effectiveness against infectiousness given infection was 23.0%.

Effectiveness of two doses against transmission of Delta was 31%.

Symptomatic/infection

Multiple studies show reduced infections, 65% to 74% after dose 1 and from 93% reduction up to no symptomatic infection in healthcare workers after dose 2.

In general population, 96.1% antibody responses after dose 1 and 98.8% after dose 2 .^

Hospitalisation

Multiple studies show effectiveness ranging from 73% to 95%.*^

As low as 0.09% of vaccinated people are hospitalised.

Transmission

Vaccination of health care workers was associated with a substantial reduction of cases in household contacts.^

Risk of household transmission 38% lower if index cases vaccinated ≥21 days prior to testing positive (compared to no vaccination).^

Effectiveness of two doses against household transmission of Delta was 42%

Secondary attack rate in households 16%.^

Mortality

Up to 97.9% effective at preventing deaths among 20-39 year olds.

Symptomatic/infection

The CDC reports low rate of new infections vaccinated people (approx.. 5800 of 77 million).^

In general population, efficacy range from 78.3% to 96.9% after 2 doses.^

In healthcare workers, the incidence of infection was 0.7% after 1 dose and 0% after 2 doses, and vaccine effectiveness was 38.2% at 14d after 1 dose and 100% after 2 doses.

VE for infection: 18-49yr: Up to 96.5%. 50-64yr: Up to 97.4%. >65yr: Up to 96.2%.

Asymptomatic

Significantly reduced risk in vaccinated adults.*

63% to 84% effectiveness from 14 days onward.

Hospitalisation

Significantly lower 14-day hospital admission rates than unvaccinated individuals.^ mRNA vaccines are 91% to 96% effective at preventing hospitalisation; 77% for partially vaccinated individuals.^

Effectiveness against any severe, critical or fatal COVID-19 disease due to any SARS-CoV-2 infection was 95.7% after the second dose,  and up to 98.2%.

As low as 0.05% of vaccinated people are hospitalised.

VE for hospitalisation: 18-49yr: Up to 97.5%. 50-64yr: Up to 97/3% >65yr: Up to 97.2%.

Mortality

mRNA vaccines 98.7% effective at preventing deaths; 64.2% effective for partially vaccinated individuals.^

Transmission

Secondary attack rate in households 10%.

Symptomatic/Infection

Between 74% to 86.6% effectiveness against infection >14 days after vaccination*^

VE for infection: 18-49yr: Up to 89.0%. 50-64%: Up to 86.1%. >65yr: Up to 80.8%.

Hospitalisation

Effectiveness was from 59% to 71%.

VE against ED visits is 73%.

Adjusted effectiveness against clinical outcomes was 72.9% for hospitalization, 92.5% for ICU admission, and 88.7% for mechanical ventilation.^

VE for hospitalisation: 18-49yr: Up to 95.7%. 50-64%: Up to 92.4%. >65yr: Up to 85.2%.

: 18-49yr: Up to 95.9%. 50-64%: Up to 92.8%. >65yr: Up to 85.5%.

Transmission

Secondary attack rate in households 20%.^

Mortality

VE against COVID-19 related deaths was 83%.

Adjusted effectiveness against clinical outcomes was 90.5% for death.^

Symptomatic/infection

VE is 90.4%. VE against moderate-to-severe cases is 100%.

VE against any VOC/VOI was 92.6%.

Safety

Initial assessment determined acceptable safety profile.

Reports of anaphylaxis (4.7 cases per 1 million doses).

Extremely rare cases of immune thrombocytopenia (<1 case per 1 million) in USA and 33 per 1 million in Europe. Rare reports of cerebral venous sinus thrombosis (CVST) and cerebral venous thrombosis. Risk of cerebral blood clots from COVID-19 is 10 times that from vaccination.

According to TGA, myocarditis is reported in around 1-2 in every 100,000 people who receive Comirnaty. For 12-17 year-old boys, the incidence rate is 13 cases per 100,000 Comirnaty doses.

Standardised incidence ratios for VTE have been reported to be at 1.29 and 0.90 after first- and second-doses.^

No association was found between vaccination, Bell's palsy, herpes-zoster or GBS.

A third dose was associated with more frequent local reactions and less systemic reactions compared to the second dose.

A fourth dose did not lead to substantial adverse events.

Initial assessment determined acceptable safety profile.

Standardised incidence ratios for VTE has been reported to be at 1.15 after first dose.^

Adjusted hazard ratios for intracranial venous thrombosis (ICVT) and of thrombocytopenia in adults aged <70 years one to 28 days after vaccination were 2.27 and 1.71, respectively.

An estimated two myocarditis events per 1 million people.

Incidence rate ratio for cerebral venous sinus thrombosis (CVST) events in the 28 days following vaccination was 1.93.

According to TGA, thrombosis with thrombocytopenia syndrome (TTS) is reported in around 2 in every 100,000 vaccinated people following first dose. The risk of TTS is much lower after the second dose (0.3 in every 100,000 vaccinated people).

TGA has found no evidence of increased risk by anaphylaxis.

Initial assessment determined acceptable safety profile.

Reports of anaphylaxis (2.5 cases per 1 million doses).

Extremely rare cases of immune thrombocytopenia (<1 case per million). Rare reports of cerebral venous sinus thrombosis (CVST); no significant link with vaccine. Risk of cerebral blood clots from COVID-19 is 10 times that from vaccination.

According to TGA, myocarditis is reported in around 2-3 in every 100,000 people who receive Spikevax. For 12-17 year-old boys, the incidence rate is 21 cases per 100,000 Spikevax doses.

A fourth dose did not lead to substantial adverse events.

Initial assessment determined acceptable safety profile.

WHO estimates that approximately 2 cases per million doses administered globally experience TTS. No TTS cases have been recorded after a second or subsequent dose.

The overall estimated observed to expected rate ratio for presumptive Guillain-Barre Syndrome was 4.18, corresponding to an absolute rate increase of 6.36 per 100 000 person-years.

Initial assessment determined acceptable safety profile.

Specific populations

Children

Aged 12-15: 100% efficacy and robust antibody responses. VE against hospitalisation 92%.

Aged 5-11: two 10-μg doses administered 21 days apart was found to be safe, immunogenic, and efficacious. VE against hospitalisation 68%-74%.

Aged 16-17: VE against hospitalisation 94%.

Adolescents

VE against symptomatic/asymptomatic infection 14 days post-first dose vaccination was 91%, and 14 days post-second dose was 99%.

VE against hospitalization was 94%, and VE against ICU admission was 98% and 98% against receipt of life support.

Aged 16-17: a booster dose restored the VE against emergency department visits and urgent care encounters to 86% from 46% at ≥150 days after the second dose.

Immunocompromised people

Multiple studies demonstrated effectiveness with few serious adverse events.^*

Compared to healthy controls, multiple studies show weaker antibody and humoral response and higher rate of infection after single and double doses.*

Breakthrough infections are 3 times higher in vaccinated immunocompromised people compared to vaccinated non-immunocompromised people.

A third vaccine dose induced strong neutralising antibody activity.

A fourth dose produced a satisfactory antibody response in some who did not respond adequately after 3 previous doses.

Antibody response to the vaccine is variable among different immunocompromised patients.

Pregnant and lactating women

Multiple studies suggest similar immune response in vaccinated pregnant and lactating women compared to vaccinated non-pregnant women, with effectiveness up to 97%.

No obvious safety signals in pregnancy or neonatal outcomes, especially in women vaccinated during third trimester.* No significant differences in side effects when receiving vaccine during any trimester.

Vaccination during the second trimester of pregnancy was associated with maternal and neonatal humoral responses.

No detectable levels of vaccine mRNA in breastmilk.* However, breast milk contained specific anti–SARS-CoV-2 IgG(S1) antibodies.

Infants who consumed post-vaccination human milk had no reported adverse effects.

Older adults

Vaccination elicited relatively lower antibody levels in older adults vs younger adults.

Aged >70: 61% effective against symptomatic infection after 28-34 days;

80-91% reduction in infection, hospitalisations and mortality among nursing home residents for up to five months.

With full vaccination, pre-Delta period adjusted VE was 74.2%. Delta period adjusted VE is 52.4%.

Rates of death during a booster program among residents of long-term care facilities decreased from 0.3 per 1000 population, to 0.1 per 1000 population 2 weeks later.

Pre-Omicron period: VE against hospitalization was 93% and 87% 14-90 and 91-180 days after the second dose, respectively; 96% 14-60 days after the third dose.^

Omicron period: VE against hospitalization was 91% and 76% 14-90 and 91-180 days after the second dose, respectively; 95% 14-60 days after the third dose.^

Aged >80: 71.4% effective at reducing hospitalisation.

Children

Aged 6-17: trial underway^

Immunocompromised people

Weaker antibody response compared to non-immunocompromised individuals, especially after single dose.*

Pregnant and lactating women

No evidence of an association between reduced fertility and vaccination. Rate of miscarriage was no higher than in controls.

Older adults

Effectiveness of the two-dose schedule was 77.9% against infection (Gamma variant), 87.6% against hospitalization, and 93.6% against death.

Aged > 65 years: 83.5% effective against symptomatic or severe infection after dose 2.

Aged >70: 60%-73% effective against symptomatic infection after 28 days; 37% effective for reducing hospital admission after dose 1.

Aged >90: 68.5% efficacy against death after dose 2.

Children

Two 25 μg doses in children aged 6 months to under 6 years elicited robust neutralizing antibody titers similar to adults.^

Two-50 µg doses in children aged 6 to under 12 years elicited higher neutralization titres against the Omicron than adults.

Provisional TGA approval for use in children (6-11yrs)

Adolescents

No serious adverse events and no cases of infection with an onset of 14 days after the second injection.

Provisional TGA approval for use in 12-17 years age group.

Immunocompromised people

Weaker antibody response compared to healthy controls^

Multiple studies show increased antibody titers in solid transplant patients after 3rd dose of either Pfizer/Moderna/Janssen.*

In immunocompromised patients, the antibody response was non-inferior to Comirnaty.

Antibody response to the vaccine is variable among patients with cancer.

A fourth dose produces a satisfactory antibody response in some who did not respond adequately after 3 previous doses.

Pregnant and lactating women

Similar immune response in vaccinated pregnant and lactating women compared to vaccinated non-pregnant women.

No obvious safety signals in pregnancy or neonatal outcomes, especially in women vaccinated during third trimester*

Maternal antibody production 5 days after dose 1, transplacental transfer of immunity to neonate 16 days after dose 1.*

Older adults

Aged ≥65: 86.4%-100% effective against infection after 2 doses.^

With full vaccination, pre-Delta period adjusted VE was 74.7%. Delta period adjusted VE is 50.6%.

Aged care residents

There is no difference in post-boost antibody levels in older adults vs younger adults.

Lower incidence of infections, symptomatic illness, hospitalisations, and death following vaccination* Report of few breakthrough infections after dose 1 in full vaccinated individuals, most with asymptomatic illness.*

Immunocompromised people

Breakthrough infection ranges from 0.8%-1.4% among solid transplant recipients.

People with rheumatic and muscular disease had a lower rate of seroconversion. One in five people did not mount a detectable antibody response.

Older adults

Aged>=65: 76.5% effective against moderate to severe COVID-19 disease.

Pregnant and lactating women

No abnormal findings in pregnancy or neonatal outcomes comparing vaccinated in third trimester versus unvaccinated pregnant women.

Older adults

Aged ≥ 65 years: 88.9%

Single dose protection*

52.4%

Reduction in positive cases range from 30%, to 84%

VE for the 14–20 day period after the first dose is 54.3% for infection and 77.3% for severe/critical disease.

67% - 77.6% VE for symptomatic infection.

VE against hospitalisation for partial vaccination (dose 1) is 33%.

VE against ICU admission for partial vaccination (dose 1) is 56%.

VE against ED visits for partial vaccination (dose 1) is 58%.

Children: VE against symptomatic disease increased to 80% within two weeks of the first dose and then declines to 40% within 8 weeks.^

73%*^

Reduction in positive cases range from 49% to 86.2%.

93.4% of previously naïve individuals seroconverted after a single dose.

VE against symptomatic COVID-19 (Gamma and Delta variants) after 21 days of one dose was 42.4%.

VE against hospitalization was 96%.

Virus specific antibodies were maintained at ≥16 weeks after receiving a single dose.

95.2%*

Reduction in positive cases ranging from 38.2% to 85.7%.

82% - 88.9% VE for infection.

VE against hospitalization was 68% up to 85%.

VE against ED visits is 73%.

One-dose VE against Delta infection is 77%.

See efficacy above (dosing schedule is single dose)

Efficacy starting 14 days after the first dose was 83.4%

Dosing schedule

Higher two-dose efficacy was observed with >6 week intervals, including in ≥80 year-olds. Increase in neutralizing antibody activity was observed with  8 to 16 weeks interval.

Antibody levels 14–35 days after dose two are higher with an extended vaccine interval (65–84 days) compared with those vaccinated with a standard (19–29 days) interval.

A third dose provided additional protection against detected infection and severe disease, particularly in immunocompromised people. In this population, a longer time interval between the second and the third dose gave a better response to the third dose.

A third dose was associated with significantly higher maternal and neonatal antibody levels.

A booster dose was associated with a significantly lower rate of SARS-CoV-2 infection and odds of testing positive.

VE >7 days after the third dose was estimated to be 88% for infection, 88%- 97% for admission to hospital, 92% for severe disease, and 81% for COVID-19-related death.

Participants who received a booster at least 5 months after a second dose had 90% lower mortality due to COVID-19 than participants who did not receive a booster.

VE of a third dose administered a median of 10.8 months after the second dose is 95.3%.

A fourth dose induced IgG antibodies and increased neutralizing antibody titers that were higher than those achieved after the third dose.

Multiple studies show a fourth dose was associated with a lower rate of infection and severe illness compared to a third dose. In adults aged 60 years and older, a fourth dose was associated with a 64%-68% and 74%-78% reduction in hospitalisation and deaths, respectively. In hospitalised patients with severe/critical breakthrough infection, a recent fourth dose was associated with significant protection against mechanical ventilation or death.^

In adults aged 80 and over, compared to the third dose, the fourth dose had an adjusted relative vaccine effectiveness of 42% against death.

Heterologous vaccination

Multiple studies show Comirnaty given as a second dose in individuals already given Vaxzevria  is safe, induced a robust immune response, and an acceptable reactogenicity profile, including at a 10–12-week interval. The antibody response is comparable to homologous vaccination.

Vaxzevria, Comirnaty, Spikevax, Novavax, Ad26.COV2.5, and CureVac as a third dose all boosted immunity after a full dose of Comirnaty.

A booster dose of Comirnaty after primary vaccination with CoronaVac provided marked increase in protection against both the infection and severe outcome.

A heterologous boosting with either Comirnaty or Spikevax provided better protection against infection after a primary dose of Johnson & Johnson than homologous boosting.

53.4% at <6-week interval between doses and 65.4% at ≥6-week interval (3)

81.3% at 12+ weeks (4)

With an 8 to 12 week interval between doses, antibody responses are 1.4 times higher.

Extending the interval between the first and second dose to 45 weeks resulted in higher antibody titres.

In recipients aged ≥80 years, two-dose VE after 14 days was 96% following a 45–64 day interval and 82% following a 65–84 day intervals.

A third dose induces antibodies to a level that correlates with high efficacy.

Vaxzevria, Comirnaty, Spikevax, Novavax, Ad26.COV2.5, CureVac, and Valneva as a third dose all boosted immunity after a full dose of Vaxzevria.

Heterologous vaccination

Multiple studies show there is a higher immunogenicity of an Vaxzevria/Comirnaty heterologous schedule compared with an Vaxzevria-only schedule. A 10–12-week interval is well tolerated and improves immunogenicity.

Reduction in the risk of infection 14 days after the second dose of Vaxzevria plus an mRNA vaccine, with effectiveness at 88%.

Robust inhibition of variants including the delta variant following heterologous boosting.

A booster shot given 6 months after the 2-dose vaccination shows increased neutralization titers.

VE of a third dose was 91% SARS-CoV-2 infection and 86% for COVID-19 hospitalization.

Heterologous vaccination

Spikevax can efficiently stimulate specific B-cell memory that has been generated by a prime dose of Vaxzevria vaccine 9 to 12 weeks earlier and may provide better protection against the B.1.351 variant than a Vaxzevria boost.

Having a dose of the Spikevax after an initial Vaxzevria or Comirnaty dose induced a higher binding and neutralising antibody response than seen after two doses of either Vaxzevria or Comirnaty.

A booster dose after primary vaccination with CoronaVac elicited a pronounced antibody response against infection.

A fourth dose induced IgG antibodies and increased neutralizing antibody titers that were higher than those achieved after the third dose.

A booster vaccination resulted in an increase in SARS-CoV-2-specific binding antibodies, neutralizing antibodies and T-cell responses when compared to single vaccination (full vaccination schedule).

VE against symptomatic infection 2-4 months since booster: 30%

Heterologous vaccination

In comparison with the homologous boost, a heterologous regimen with mRNA-based vaccines showed a significantly larger increase. Spikevax boosting was the most immunogenic, associated with higher reactogenicity.

A booster dose with Ad26.COV2.S vaccine substantially increased spike-specific CD8+ T cells in the recipients of primary mRNA vaccines.

VE against symptomatic infection 2-4 months after 1 Johnson & Johnson/1 mRNA dose: 55%

VE against COVID-19–associated emergency department/urgent care visits after 1 Johnson & Johnson/1 mRNA dose: 79%

VE against COVID-19–associated hospitalisation after 1 Johnson & Johnson/1 mRNA dose: 78%

Not yet available

Prior COVID-19 infection

Most studies report prior infection enhances neutralising antibody response, including following a single dose and at 2-3 weeks after second dose.

Antibody response to vaccination was broader and more durable in recovered versus naïve.

Multiple studies indicate a greater humoral response than uninfected individuals after a second dose.

Individuals who were previously infected then vaccinated had 82% decreased risk of reinfection, and 76% decreased risk of symptomatic disease compared to previously infected but remained unvaccinated individuals.

Effectiveness of two doses of mRNA vaccines against hospitalisation did not wane across 11 months among individuals previously infected with non-Omicron.^

Humoral immune response after vaccine doses in individuals infected >6 months prior was shown to be at least similar to those recently infected.

Incidence rates of infection among vaccinated persons with prior infection was estimated at 1.66 per 10,000 person-weeks.

Elderly populations can mount a strong antibody response upon receiving a single dose 15 months after recovery from COVID-19.^

Hybrid immunity resulting from prior infection (especially during Delta predominant period) and recent booster vaccination confered the strongest protection against symptomatic BA.1 and BA.2 Omicron infections and severe COVID-19.^

Prior infection significantly increased antibody peak level and half-life

Incidence rates of infection among vaccinated persons, with and without prior infection, were estimated at 1.55 and 1.83 per 10,000 person-weeks.

Following primary vaccination, individuals with pre-existing immunity showed higher induction of all antibodies but IgG3. However, COVID-19 recovered subjects did not mount a recall antibody response upon the second vaccine dose.

Among previously infected individuals, VE against hospitalisation during Omicron predominant period compared to unvaccinated individuals: 35.9%

Not yet available

Not yet available

Longevity of protection and waning immunity

Decline in humoral response six months after receipt of the second dose of the Comirnaty vaccine. However, protection against hospitalization and death persisted at a robust level for six months after the second dose.

Neutralizing activity against Delta variant was detectable after eight months.

87% of immunocompromised adults had adequate antibody titres 1.5 months after the second dose, but only 41% maintained adequate antibody titres three months after vaccination.

Effectiveness against infections declined from 88% during the first month after full vaccination to 47% after 5 months.

VE against Delta was 93% in the first month but declined to 53% after 4 months.

VE against hospital admissions for infections with Delta was 93% for up to 6 months.

VE to reduce infection drops to 70.1% after 7 months; VE to reduce hospitalisation and death stays above 87% through 7 months.^

VE against any PCR-confirmed infection declined from 87% at 0-2 months after the second dose to 53% at 7-8 months.

Breakthrough infections in fully vaccinated individuals have lower viral loads, however this effect ultimately vanishes after 6 months but is restored after a booster dose.

At 6 months of follow-up after the second dose, the estimated cumulative incidence of breakthrough infection was 0.84%.

Among previously uninfected persons who had received 2 doses of vaccine, the number of cases of SARS-CoV-2 infection per 100,000 person-days at risk (adjusted rate) increased from 21.1 among those who had been vaccinated less than 2 months previously to 88.9 among those who had been vaccinated at least 6 months previously.

The effectiveness of three doses against hospital admission and emergency department admission due to Omicron waned after three months to 55% and 53%, respectively.

In non-immunocomprimised patients, VE against emergency department/urgent care visits and hospitalisation 120-179 days after a third dose was 75% and 84%, respectively.

After a third dose, VE against hospitalisation peaked at 90·8% against Omicron BA.1 sub-lineage and 89·1% against BA.2 before decreasing to 80·4% and 56·5%, respectively, after 15 or more weeks.

Generally, adenoviruses are highly immunogenic, driving long-lasting immune responses*^

Virus specific antibodies were maintained at ≥16 weeks after receiving a single dose.

Effectiveness against symptomatic disease after second dose is 47% by 20+ weeks against the Delta variant. Protection against hospitalisation is 77% effectiveness by 20+ weeks. Effectiveness against deaths was 79% by 20+ weeks for all ages.

VE against any PCR-confirmed infection declined from 83% at 0-2 months after the second dose to 55% at 7-8 months.

Likely to offer protection for a “couple of years”, as antibody decay is very slow.*^

In one study antibodies persisted through 6 months after the second dose. While another found at 6 months, a sharper decline in antibody levels is observed in naïve vaccinees compared to previously infected people.

Effectiveness against symptomatic disease after second dose is 90-96% at 10-14 weeks.

VE to reduce infection drops to 81.9% after 7 months; VE to reduce hospitalisation and death stays above 90% through 7 months.

VE against any PCR-confirmed infection declined from 90% at 0-2 months after the second dose to 65% at 7-8 months.

To date, there is no evidence on the effect of waning vaccine immunity and its relationship to onward transmission.

Booster shot for adults under evaluation by TGA.

At 6 months of follow-up after the second dose, the estimated cumulative incidence of breakthrough infection was 0.59%.

Neutralisation titers against the Omicron variant remained detectable six months after the booster dose.

Generally, adenoviruses are highly immunogenic, driving long-lasting immune responses*^

Elicits durable humoral and cellular immune responses with minimal decreases for at least 8 months after immunization.

VE to reduce infection drops to 59.4% after 5 months; VE to reduce hospitalisation and death stays above 80% through 5 months.

Not yet available

Impact of new variants on vaccines

Alpha: Estimated effectiveness up to 94.5%.^ Risk of infection was 5.75 events per 1000 persons.

Beta: Estimated 5 to <10-fold reduction in neutralisation. Estimated effectiveness from 72% up to 100%.^

Gamma: Estimated 5 to <5-fold reduction in neutralisation. Estimated effectiveness up to 82%.

Delta: Estimated 5 to <10-fold reduction in neutralisation.^ Estimated effectiveness ranges from 50% to 92%.^
Vaccine effectiveness in adolescents is 91.5% against infection.

VE decreased less against hospitalization to 91.7%, and death to 91.9%.

Omicron:  A 20- to 40-fold reduction in neutralising activity by two doses of Comirnaty compared with other strains^

Two doses of Comirnaty offers 70% protection against hospitalisation.

booster dose of Comirnaty resulted in an increase in neutralising activity irrespective of primary vaccination type.

A booster dose conferred a high effectiveness (68.8%) in preventing infections with Omicron variant; and a high effectiveness (84%-89%) against Omicron-related hospitalisation and and ICU admission (92%) up to four months following vaccination. ^

In previously non-Omicron infected individuals and individuals vaccinated with two doses only, Omicron sub-lineages BA.1.1, BA.1, and BA.2 exhibited substantial immune escape. mRNA vaccine booster dose recovered immunity to levels comparable to Dela.

VE against symptomatic disease is similar for BA.1 and BA.2 sub-lineages.

A booster dose induced similar neutralising antibody titers against the Omicron BA.1 and BA.2 sub-lineages.

A fourth dose was associated with a lower rate of infection and severe illness compared to a third dose.

Alpha: Estimated 5 to <10-fold reduction in neutralisation.^ Estimated effectiveness up to 74.6% -  91%.

Beta: Estimated 5 to <10-fold reduction in neutralisation.^ As little as 10.4% protection against mild to moderate disease, up to 48% effective against symptomatic disease.^

Gamma: Estimated 2 to <5-fold reduction in neutralisation.^ VE of 64%. Starting 14 days after the second dose, effectiveness is 77.9% against infection, 87.6% against hospitalization, and 93.6% against death.

Delta: Estimated 2 to <5-fold reduction in neutralisation.^ Estimated effectiveness from 64% to 91%. Effectiveness after one dose was notably lower compared with the alpha variant.
Estimated effectiveness against death 84.8% to 91%.

VE against SARS-CoV-2 infection of 63·1%. VE of vaccination against moderate-to-severe disease of 81·5%.

Omicron: Preliminary studies suggest reduced effectiveness against symptomatic disease at 15 weeks after the second dose*^, however, a booster dose of Comirnaty resulted in an increase in neutralising activity irrespective of primary vaccination type (~71% for those who received Vaxzevria)*^

Alpha: Estimated <2-fold reduction in neutralisation.^ Estimated effectiveness against infection 92%-100%. Risk of infection was 4.52 events per 1000 persons.

Beta: Estimated 5 to <10-fold reduction in neutralisation.^ Estimated effectiveness up to 96.4%.

Gamma: Estimated 2 to <5-fold reduction in neutralisation.^ Estimated effectiveness up to 77%.^

Delta: Estimated 2 to <5-fold reduction in neutralisation.^ Estimated effectiveness from 56.6% to 86.7%.^

Omicron: Preliminary studies suggest low-absent neutralisation; however, a booster mRNA may reduce risk of symptomatic breakthrough infections and prevent hospitalisation*^

The 2 dose VE against Omicron infection at 14-90 days was 44.0% but declined quickly. The 3 dose VE was 71.6% and 47.4% against Omicron infection at 14-60 days and >60 days, respectively.

VE against symptomatic disease similar for BA.1 and BA.2 sub-lineages.^

A booster dose was associated with neutralization titers against the Omicron that were 20 times higher than those assessed after the second dose of vaccine.

Two doses in adolescents (100 µg) and children (50 µg) elicited higher neutralisation responses against Omicron than those of adults.

Alpha: Estimated 2 to <5-fold reduction in neutralisation.^

Beta: Estimated ≥10-fold reduction in neutralisation.^ Estimated effectiveness up to 85%.

Gamma: Estimated 2 to <5-fold reduction in neutralisation.^

Delta: Estimated <2-fold reduction in neutralisation.^

Overall VE against hospitalisation for fully vaccinated = 91%.

Omicron: Neutralisation capacity against Omicron was maintained best against sera from individuals infected and vaccinated or vaccinated and infected*^

VE against symptomatic infection during the periods of 14 days-1 month and 2-4 months since last dose:  17.8% and 8.4% after 1 dose; 27.9% and 29.2% after 2 doses; 61.3% and 54.3% after a second dose with a mRNA vaccine.

VE against COVID-19 associated emergency department/urgent care visits: 24% after 1 dose, 54% after 2 doses

VE against COVID-19 associated hospitalisation: 31% after 1 dose, 67% after 2 doses

Alpha: Estimated <2-fold reduction in neutralisation.^ Estimated effectiveness from 86.3% up to 89.7%.^

Beta: Estimated ≥10-fold reduction in neutralisation.^ Estimated effectiveness up to 81.7% for severe to critical disease.^

Storage

-80°C and -60°C

-20±5°C for up to 2 weeks within the shelf life when stored at -90 to -60°C 2°C to 8°C for unopened thawed vials up to 31 days.^

2°C to 8°C

-25°C and -15°C

2°C to 8°C: Unopened for up to 4.5 months.

2°C to 8°C: Opened up to 6 hours.

Freezer at -25°C to -15°C: Up to 24 months to the expiry date.

2°C to 8°C

Study participants

43,548 enrolled, 43,448 received injections (randomly assigned 1:1 ratio) (1)

596,618 vaccine recipients matched 1:1 ratio to controls. (2)

23 848 enrolled, 11 636 included in interim primary efficacy analysis (randomly assigned 1:1 ratio) (3)

17178 participants included in the efficacy analysis after a further month of data collection from original Lancet article* (4)

30,420 enrolled (randomly assigned 1:1 ratio)

44,325 enrolled, 43,783 received vaccine or placebo (randomly assigned 1:1 ratio)

15,187 enrolled, 15,139 underwent randomisation (randomly assigned 1:1 ratio)

14,039 participants met the criteria for the per-protocol efficacy population

Study population

49% female, 35% obese, 21% at least one coexisting condition. Majority White (83%). Median age 52 years; 42% older than 55y (1)

Participants from Clalit Health Services data, which insures 4.7 million patients (53% of the population). (2)

Majority aged 18–55 years (86.7% in UK; 89.9% in Brazil cohort). 60.5% female. Majority White (91.4% in UK; 66.6% in Brazil)

47.3% female, mean age 51.4 years; 24.8% were 65 years of age or older. Majority White (79.2%)

45.0% female, median age 52 years; 33.5% were 60 years of age or older. Majority White (58.7%).

Latin America 40.9%; South Africa 15.0%; US 44.1%

45.0% female, median age 52 years; 33.5% were 60 years of age or older. Majority White (58.7%). Latin America 40.9%; South Africa 15.0%; US 44.1%

Phase 3 trials reported in the grey literature  / press releases

Vaccines which have had initial results from phase 3 trials reported in the grey literature and press releases will be reported here. The information will be added to the living table once results are published in the peer reviewed literature. Recent phase 1 and 2 trial results have been included below, however this is not a complete list of early trial data.

The TGA recognise the following vaccines for the purpose of travel to Australia:

  • Coronavac (Sinovac)
  • Covidshield (AstraZeneca - Serum Institute of India)
  • BBIBP-CorV for people aged 18 - 60 years of age (Sinopharm China)
  • Covaxin (Bharat Biotech)
  • Sputnik V (Gamaleya Research Institute)

Notes

Table includes COVID-19 vaccines published as a peer-reviewed phase 3 trial (preliminary or final results). Data is included on these vaccines from additional publications. Studies that capture outcomes in real world settings are tabulated under effectiveness.

* Preliminary data, not fully established, in some cases small numbers or short follow up, or based on previous data; interpret with caution.

^ Commentary, grey literature, pre peer review or news.

ꝉ Asymptomatic/unreported symptoms. Efficacy estimated by study by pooling all cases and applying to entire cohort of sub studies; interpret with caution.

ⱡ Onward transmission in a vaccinated individual.

ⱶThis figure was not reported in the paper but was included on the same basis of the Moderna results for severe COVID-19.

LD/SD = low dose/standard dose and SD/SD = standard dose

Pfizer has two phase 3 trials published (1) and (2), as does Oxford/Astra-Zeneca (3) and (4) and Sinovac (5) and (6).

Modelling studies estimating real world effectiveness are not included in the table.

Where multiple studies are available on an outcome, not all studies are hyperlinked. Those that are more recent, published in peer reviewed journals and are higher on the evidence hierarchy are generally linked.

The "last updated" date refers to the date when the evidence was last reviewed.

Background

Living evidence tables include some links to low quality sources and an assessment of the original source has not been undertaken. Sources are monitored regularly but due to rapidly emerging information, tables may not always reflect the most current evidence. The tables are not peer reviewed, and inclusion does not imply official recommendation nor endorsement of NSW Health.

Last updated on 10 Jun 2022

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