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How true is the claim that moderna vaccine is 100% effective against severe COVID-19?

Claim: A Twitter post claims Moderna vaccine has 100% effectiveness against severe coronavirus infection.

How true is the claim that moderna vaccine is 100% effective against severe COVID-19?

True. While the moderna Vaccine is 94.5% effective against normal COVID-19 cases, it is 100% effective against severe COVID-19 as none of those who received the vaccine during trial developed severe COVID-19.

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A Twitter post by @spectatorindex shared on Monday November 30, 2020, claims moderna’s coronavirus vaccine is 100% effective against severe coronavirus infection. 

This post has so far generated 8,305 retweets and 4,012 quote tweets and 35.8 thousand likes.

“BREAKING: Moderna’s coronavirus vaccine shows an efficacy of 100% against severe coronavirus infections”

Excerpt of the Twitter post.

How true is the claim that moderna vaccine is 100% effective against severe COVID-19?
Screenshot of the Twitter post.

Screenshot of the Twitter post.


Dubawa conducted a keyword search on the Moderna Vaccine and coronavirus.

What is the Moderna vaccine?

Moderna vaccine identified as mRNA-1273 is a vaccine in response to the threat of coronavirus by a biotechnology company named Moderna founded in 2010. 

This company focuses on mRNA science and is pioneering a new class of medicines made of messenger RNA, or mRNA. The potential implications of using mRNA as a drug are significant and far-reaching and could meaningfully improve how medicines are discovered, developed and manufactured. 

Also, a Youtube video with details of the vaccine shows the phases this vaccine went through.

How true is the claim that moderna vaccine is 100% effective against severe COVID-19?
Screenshot of Youtube Video on mRNA-1273 (Moderna Vaccine).

Dubawa also studied the World Health Organisation’s (WHO) draft landscape for candidate vaccines. The document showed that the Moderna/NIAID vaccine is among the 48 WHO’s candidate vaccines in clinical evaluation.

How true is the claim that moderna vaccine is 100% effective against severe COVID-19?
Screenshot of WHO draft landscape of COVID-19 candidate vaccine.

What is the update on the Moderna vaccine (mRNA-1273) 

A report by Associated Press (AP) noted that Moderna Inc. made it known on Monday that it would be asking the United State (U.S.) and European regulators to allow emergency use of its COVID-19 vaccine. This it said is because results of a new study  confirm the shots offer strong protection.

A similar report by the New York Times noted that Moderna is seeking this emergency approval to ensure first shots of its vaccine are given as early as December 21 as the number of COVID-19 cases continues to rise.

In another report, the British Broadcasting Corporation(BBC) noted that Moderna is filing for US and European emergency regulatory approval of its coronavirus vaccine so it can be recommended for widespread use. Clinical studies show it is more than 94% effective at protecting people from becoming ill with Covid-19.

Moderna application is the second application, coming two weeks after Pfizer and BioNTech.’

How effective is Moderna vaccine 

A report by The Guardian noted final results confirm the Moderna vaccine has 94% efficacy. 

Another report by BBC noted the vaccine shows near 95% effectiveness.

A similar report by Science Magazine noted that no one who got the Moderna vaccine in trial developed severe COVID-19.

In a look at the Moderna website Dubawa studied an Infographic that contained a timeline summary of the different stages of the vaccine. This timeline showed that as of November 16, the vaccine shows the vaccine so far has 94.5% efficacy. 

How true is the claim that moderna vaccine is 100% effective against severe COVID-19?

Screenshot of Moderna site.

Moderna also in a publication on its site on November 30, 2020 noted that its vaccine is 94.1% effective against COVID-19 and 100% effective against severe COVID-19. 

How true is the claim that moderna vaccine is 100% effective against severe COVID-19?

Screenshot of Moderna’s publication.

What is the difference between COVID-19 and Severe COVID-19?

While the spread of COVID-19 continues to rise, the severity has been seen to vary from mild to moderate, and then to severe. A London-based GP and GP trainer, Dr Mary Lowth, believes the public would benefit from knowing the difference between these severity levels. 

Doctors have used different terms to describe COVID-19 severity. Terms like; Asymptomatic, Mild, Moderate, Severe, and Critical have been used. 

Most people who are young and healthy are likely to be in group 2 (mild) or 3 (moderate).

Asymptomatic cases

Being asymptomatic simply means that a COVID-19 patient does not have symptoms of the virus.

Mild COVID-19

Mild cases are seen in most healthy people under 60 who have symptoms. The symptoms typically last about 7 to 10 days.

As many as 80% of symptomatic cases are mild and remain mild in severity. However, it is noteworthy that people with mild illness can take a turn for the worse, especially those in vulnerable groups.

The main symptoms of mild COVID-19 include: Temperature (in 90% of cases), a dry cough (70%), tiredness (40%), feeling slightly breathless (20%), muscle pain (15%), headache (15%), sore throat (14%), and diarrhoea (4%).

Moderate COVID-19

When the illness gets worse, it becomes a moderate case which is said to be common and may last for around 7 to 14 days.

People with moderate illness are more breathless and tend to have an increased heart rate, when moving around.  

In addition to the symptoms you may get with a mild COVID-19, moderate COVID-19 patients may also experience a temperature higher than 37.8C, feeling breathless when doing moderate exercise (such as walking up stairs), soreness from coughing, but no pain, a more persistent cough, several times an hour, a headache, particularly if you’re hot with tiredness,  a need to stay in bed and with a dry mouth.

Severe COVID-19

People with a severe form of the illness may develop pneumonia, Severe cases are more likely seen in older people or people with any health conditions that make them vulnerable. 

Severe cases are not impossible in those who are healthy, but they are less common.

Symptoms of severe COVID-19 infection and the resulting pneumonia include: extreme breathlessness – you can’t do much or speak easily, pain in your chest, tummy or back when you breathe, a high temperature, a tight chest, lacking the desire to eat or drink, seeming confused to others, bluish lips or face.

Other common symptoms of pneumonia caused by the illness include: rapid and shallow breathing, fast heartbeat, unwell appearance, and lowered blood pressure.

The Centre for Disease Control and Prevention (CDC) defined Severe illness from COVID-19 as hospitalization, admission to the ICU, intubation, mechanical ventilation, or death.

It also noted that adults of any age with underlying illnesses, like cancer, chronic kidney disease, chronic obstructive pulmonary disease (COPD), health conditions( heart failure, coronary artery disease, or cardiomyopathy), weakened immune system from solid organ transplant, obesity, pregnancy, sickle cell disease, smoking, asthma type 1 and 2 diabetes mellitus, cystic fibrosis, hypertension, liver disease, etc., may be affected.

Medscape also defined severe COVID-19 any case of COVID-19  associated with dyspnea, hypoxia, or greater than 50% lung involvement in imaging. It may also be associated with respiratory failure, shock, or multiorgan system dysfunction.

Medscape noted that severe or acute COVID-19 can be managed by providing supportive care of complications, including advanced organ support for respiratory failure, septic shock, and multiorgan failure. 

It also said that empiric testing and treatment for other viral or bacterial etiologies may be warranted and patients with severe or critical COVID-19 are likely to require aerosol-generating procedures, so they should be placed in an airborne infection isolation room (AIIR), if available.

Critical COVID-19

The patients here are very unwell and develop severe pneumonia. A condition called severe acute respiratory syndrome (SARS) can develop (i.e when the small air sacs in the lungs become so inflamed and wet that they stick shut and the surfactant can’t hold the tiny air sacs open). If this happens, you’ll need a ventilator to help inflate your lungs.

In the worst cases, people can develop sepsis, which causes other organs to stop working. It’s possible to survive critical COVID-19 if you have intensive care help, but even that is not always enough.


The claim that Moderna is 100% effective against severe COVID-19 is true from the data released by Moderna company and other media reports.

While the vaccine is 94.5% effective against COVID-19, it is 100% effective against severe COVID-19 as it was reported that no one given the moderna vaccine during trial developed severe COVID-19.  

However, it is worthy of note that while Moderna is seeking approval to roll out its vaccine following the result of effectiveness, regulators will look at trial data for the mRNA vaccine and decide if it is safe and effective enough to recommend for roll out.

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