EXPERT REACTION: Moderna vaccine reports 100% efficacy against severe COVID

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Randomised controlled trial: Subjects are randomly assigned to a test group, which receives the treatment, or a control group, which commonly receives a placebo. In 'blind' trials, participants do not know which group they are in; in ‘double blind’ trials, the experimenters do not know either. Blinding trials helps removes bias.

People: This is a study based on research using people.

Overnight, Moderna has reported further results of their Phase 3 COVID vaccine study. The results, based on 30,000 participants, included 196 cases of COVID-19, of which 30 cases were severe. According to the company, the vaccine's efficacy was 94.1 per cent overall. The data also suggest the vaccine is 100 per cent effective against severe COVID-19. Moderna also announced it will request Emergency Use Authorization (EUA) from the US Food and Drug Administration (FDA), and apply for a conditional marketing authorisation with the European Medicines Agency (EMA).

Organisation/s: Moderna

Funder: Moderna/ U.S. Department of Health and Human Services (BARDA)


Expert Reaction

These comments have been collated by the Science Media Centre to provide a variety of expert perspectives on this issue. Feel free to use these quotes in your stories. Views expressed are the personal opinions of the experts named. They do not represent the views of the SMC or any other organisation unless specifically stated.

Professor William (Bill) Rawlinson is a Senior Medical Virologist, Director of Serology, Virology and OTDS Laboratories (SAViD) and Professor at UNSW

The Moderna vaccine for SARS-CoV-2 is a significant advance and will be very important to see the full data. The efficacy is very exciting, and clearly needs to be reviewed. That notwithstanding, it is consistent with the other mRNA vaccine results, and represents a truly exciting prospect.

This is one of the first mRNA vaccines in humans, and the relative benefits of such vaccines around production, licensing and expansion are tremendous. The ability to use the technology in different settings, and as demonstrated, the ability to rapidly develop these vaccines is a significant step forward.

Given the different vaccines now in development, and the results of these trials to date, it is to be hoped the low adverse effect trials have shown so far will continue into larger population studies. Continued monitoring of these programs post-delivery of vaccines will be important.

Last updated: 02 Dec 2020 4:52pm
Declared conflicts of interest:
Bill has declared that Moderna have approached him about being involved in a trial of an mRNA vaccine for Cytomegalovirus.
Professor Kim Mulholland is Group leader for new vaccines at the Murdoch Children's Research Institute, a Professorial Fellow at the University of Melbourne Department of Paediatrics and Professor of Child Health and Vaccinology at the London School of Hygiene and Tropical Medicine

Moderna has released the data required for Emergency Use Authorization, initially in the US and then globally. The data describe 30,000 participants, half of whom received two doses of vaccine, who were followed for about two months.

The 15,000 who received the placebo (ie. did not receive the vaccine) suffered 185 cases of COVID-19, including 30 severe cases and one death.  The 15,000 who received the Moderna vaccine suffered only 11 cases of COVID-19, none severe. 

This indicates 94% protection and is an excellent result, particularly the finding that severe disease is prevented. However, there are some causes for concern:

  • African-Americans have been badly affected by COVID-19 with a mortality rate three times that of white people, yet, while 18% of US citizens are African-American, only 3% of cases were in this group, presumably reflecting enrolment in the trial. This is unfortunate.
  • How long will protection last? Of course this is not known at this stage, but to determine this, it would be optimal if the 30,000 participants continued with the trial.  We should know if this is planned, or are the unvaccinated group to be offered the vaccine? If the trial is to be effectively terminated, how will we ascertain the duration of protection?
Last updated: 01 Dec 2020 6:59pm
Declared conflicts of interest:
Member of Safety Monitoring Committee for Novavax Covid-19 vaccine trials in USA and South Africa. Member of the WHO Strategic Advisory Group of Experts (SAGE) on immunization
Dr Rob Grenfell is CSIRO's Health and Biosecurity Director

The global race against the COVID-19 pandemic is gaining momentum as vaccine developers around the world are close to completing their phase III clinical trials. 

The latest provisional data analysis from Moderna’s phase III trials are promising, and Moderna joins a number of other vaccine developers who have released encouraging data on their candidates’ safety and efficacy in the past month. 

As always it is important to remember these results are yet to be peer-reviewed and published in a scientific journal, which in turn will allow greater scrutiny and independent assessment by the global scientific community. 

From a public health perspective, we want to see as many vaccines as possible reach this stage and to pass regulatory approvals should they prove to be safe and effective. Not all vaccines have the same level of efficacy across different demographics, so it is important to have options that work across the broader population. 

Seasonal flu vaccines are usually around 60-70% efficacious, so to have Moderna join a number of other vaccine candidates that have provisionally reported levels of efficacy over 90% is very encouraging to see. 

We must remember that we are still some time away before COVID-19 vaccines will be made available to the general public in Australia. But we can have confidence in the regulatory rigour that any vaccine will be put through by the Therapeutic Goods Administration before it is released in Australia.

Last updated: 01 Dec 2020 2:20pm
Declared conflicts of interest:
CSIRO was involved in pre-clinical trials for AstraZeneca and Inovio Pharmaceuticals vaccine candidates
Dr Roger Lord is a senior lecturer (Medical Sciences) with the Faculty of Health Sciences at The Australian Catholic University and Visiting Research Fellow with The Prince Charles Hospital (Brisbane)

The latest phase 3 trial results for the Moderna COVID-19 vaccine are certainly encouraging. The trial includes individuals from different ethnic backgrounds and age groups and appears to be well tolerated.

The reported vaccine efficacy of 94.1% is however based on only 11 individuals who received the mRNA-123 vaccine. It remains to be seen if these high efficacy values are maintained when more vaccinated individuals are examined.

Last updated: 01 Dec 2020 2:17pm
Declared conflicts of interest:
None declared.
Paul Griffin is Director of Infectious Diseases at Mater Health Services, Associate Professor of Medicine at the University of Queensland, and Medical Director and Principal Investigator at Q-Pharm, Nucleus Network

More exciting news from Moderna overnight with further information reported from their large phase 3 clinical trial. This trial is large, now enrolling over 30,000 participants. Of 196 confirmed cases, 185 were in participants who received placebo as compared to 11 who had received the vaccine, giving a reported efficacy (for this endpoint) of over 94 per cent.

Importantly, it also appeared effective at preventing severe disease, with 30 severe cases observed in this trial. However, they all occurred in participants who had received placebo and none were observed in participants who received the vaccine.

As with all media releases we still need to see the full dataset and await publication of the study in a peer-reviewed journal. However, this level of efficacy, with a reportedly favourable safety profile, would certainly support proceeding with regulatory approvals which are now underway.  

Therefore, providing the review of the full dataset by the relevant panels of experts responsible for these regulatory reviews shows the safety and efficacy is indeed as reported, this vaccine should be available for use in the very near future. This is another huge step forward in our efforts to combat SARS-CoV-2.

Last updated: 01 Dec 2020 11:50am
Declared conflicts of interest:
None declared.
Professor Raina MacIntyre is Head of the Biosecurity Program at the Kirby Institute at the University of NSW. She is an expert in influenza and emerging infectious diseases.

The reported short-term efficacy of the Moderna vaccine is very encouraging - over 94 per cent, and 100 per cent against severe disease. This, and the Pfizer vaccine, show that mRNA vaccines are feasible, and this represents breakthrough technology a long time in the making, which has emerged against the odds and with major setbacks in decades past.

We do need to see the peer-reviewed publication of the phase 3 trial, and be mindful that the longer-term efficacy is unknown. Current trials are only reporting efficacy at three months or so. We need to know the duration of immunity over one to five years, and that data will take time to accrue. 

For Australia, it is unlikely this vaccine will be among the first, as the company has made commitments to supply the US, and we do not have an agreement with Moderna.  However, the bigger picture is that there is an excellent prospect for an exit strategy with efficacious vaccines.

Last updated: 01 Dec 2020 11:49am
Declared conflicts of interest:
None declared.
Professor Sarah Palmer is the Co-Director of the Centre for Virus Research at The Westmead Institute for Medical Research and Professor in the Faculty of Medicine at the University of Sydney

The results of this limited analysis from Moderna are encouraging, especially as the number of COVID-19 cases skyrocket in the United States.

Although this means that highly effective COVID-19 vaccines could be available in a matter of weeks, it remains unclear which type of protection the Moderna and Pfizer coronavirus vaccines provide.

If they only prevent illness, not infection, vaccinated people could still spread the disease to others.

How long immunity lasts after vaccination is also an open question. Even if we can favourably cross those hurdles, mass-producing the vaccines and distributing them to hospitals, primary care practices, and pharmacies for billions of people will be an enormous and time-consuming task. 

In the meantime, societies must not become complacent and remain vigilant as to the preventative measures needed to slow the spread of this deadly disease.

Last updated: 01 Dec 2020 11:48am
Declared conflicts of interest:
None declared.
Professor Gregory Tannock is an Emeritus Professor and Visiting Fellow at the Burnet Institute

No data is adduced as to why the Moderna vaccine is more thermostable, with respect to storage, than the Pfizer vaccine.
Descriptions of in vivo or in vitro data for ether vaccine do not include in vivo (in animal models) or in vitro [in the test tube] data on the susceptibility of the ss-RNA active component of either vaccine to RNAse degradation following administration. This data must exist and would not be a concern for other vaccines where the active component is a virion protein or an attenuated whole virus.

Last updated: 01 Dec 2020 11:48am
Declared conflicts of interest:
None declared.

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