Close

COVID-19 Update

What we know now about COVID-19 – December 2021 Edition

A review of COVID-19, Vaccines and Variants

As 2021 comes to a close, our Executive Director Professor Jason Kovacic discusses the latest advice and research relating to COVID-19 including vaccines, boosters and long COVID and what we know so far about the Omicron variant.

Professor Kovacic, what sort of heart complications can arise as a result of COVID-19 infections?

COVID-19 can affect the cardiovascular system in many ways, including causing widespread inflammation that can lead to lung damage and heart muscle damage, and cause cardiovascular complications including:

  • Blood clots – these most commonly form in the legs and can then travel to the lungs. When a blood clot goes to the lungs it is called a pulmonary embolism. Pulmonary embolism can be fatal. Blood clots are reported to occur in 15-20% of people with severe COVID infection.
  • Increased inflammation – this is a common and major feature of COVID-19 infection. This massive inflammatory response can progress to heart and lung injury and impaired cardiac function.
  • Myocarditis – this is inflammation of the heart muscle. It seems that in the case of COVID-19, this can be via direct viral infection of the heart muscle but also importantly from the massive inflammatory response that is triggered by COVID-19.
  • Heart failure – this is when the heart isn’t able to pump blood as effectively as it normally should. Myocarditis from COVID-19 is a common cause of heart failure in the setting of COVID infection. The massive inflammatory response with COVID-19 can also cause heart failure.
  • Heart attack – this can be triggered in a number of ways by COVID-19 infection. This includes small blood clots in the arteries to the heart; due to the massive inflammatory response seen with COVID-19 infection causing a ‘plaque rupture’ that is the usual cause of myocardial infarction; or via other ways.
  • Heart rhythm problems – these can be seen in addition to the above heart problems.
Man having his blood pressure checked by a doctor

Are people with cardiovascular disease more at risk of complications if they catch COVID-19?

Yes, people with significant cardiovascular disease are at higher risk of serious complications from COVID-19. So that’s not everybody who has ever seen a cardiologist – but people with significant cardiac issues. These people with significant cardiovascular disease are more likely to be hospitalised and die from the virus, and COVID-19 can also make a person’s existing cardiovascular condition worse.

As well as cardiovascular disease, other health problems common in people hospitalised with COVID-19, and associated with an increased risk of death, include high blood pressure, obesity, diabetes and and a prior heart attack.

Your best way to avoid getting COVID-19 is to get vaccinated and get a booster after six months, as well as the flu vaccine. In general, pre-existing cardiac conditions are not regarded as a contraindication to vaccination.

Positive behaviour changes like a healthy diet, exercise, and quitting smoking will also help.

A new COVID-19 strain has been identified – Omicron – is there any indication yet whether this variant causes different or more severe heart-related complications than other variants?

There is very little data about the nature of the infection with the Omicron variant of COVID-19 currently. As far as we are aware, as of early December 2021, there is no data yet about the effects of the Omicron variant on the heart and whether its effects are more severe, similar, or less severe than other variants.

What do we know about the Omicron variant so far?

This mutated variant was recently discovered in South Africa by whole genome sequencing.

According to the Garvan Institute of Medical Research, Omicron is overtaking Delta in almost every precinct of South Africa at a much faster speed compared to the rate that Delta overtook Beta. This indicates the variant is likely to be much more contagious than earlier variants.

The World Health Organization says studies into the new variant are continuing and that, at the moment, it is not yet clear whether Omicron is more transmissible. The WHO also says it is unclear whether infection with the new variant causes more severe disease, but early data indicates an increasing rate of hospitalisations in South Africa.

Currently, there are no unusual symptoms being reported following infection from the mutated variant.

Do the current vaccines give protection against this new variant?

Early data from South Africa’s National Institute for Communicable Diseases suggests although Omicron looks likely to evade some immunity, the existing vaccines, such as Pfizer, Moderna and AstraZeneca should still protect again severe illness and death.

Learn more from the National Institute for Communicable Disease by visiting their FAQ on the new variant.

How do heart-related adverse effects of COVID-19 vaccines differ to those caused by the disease itself? Does the disease or the vaccine carry more risk to heart health?

As of December 2021, almost 40 million doses of a COVID-19 vaccine had been given in Australia, with around eight billion doses administered worldwide.

For most, including those with cardiovascular disease, the benefits of vaccination against COVID-19 overwhelmingly outweigh any risks.

The COVID-19 vaccines have been subjected to very intense monitoring and have been safe in the vast majority of people.

Very rare heart-related side effects have been reported for both the mRNA (Pfizer and Moderna) and adenovirus-vector vaccines (Johnson & Johnson and AstraZeneca), but these events occur much less frequently than the often severe and life-threatening heart-related complications that can occur with COVID-19 infection that are discussed above.

While rare, the main potential heart-related side effects are myocarditis (heart inflammation) or pericarditis (inflammation of the outer lining of the heart) from the mRNA vaccines (Pfizer and Moderna), or blood clots from the adenovirus-vector vaccines (the AstraZeneca and Johnson & Johnson vaccines).

Occurrence of cardiovascular side effects associated with COVID-19 vaccines vs COVID-19 infection
Occurrence of cardiovascular side effects associated with COVID-19 vaccines vs COVID-19 infection

Pericarditis and myocarditis after mRNA COVID-19 vaccines have been reported most in males under 30 years of age, and most commonly after the second vaccine dose. The large majority of these cases have been mild, and patients have recovered quickly.

Symptoms of myocarditis or pericarditis typically appear within one to five days of an mRNA vaccine dose and may include chest pain, heart palpitations, fainting or shortness of breath. People who experience any of these symptoms after having an mRNA COVID-19 vaccine should seek prompt medical attention.

The other major cardiovascular complication seen has been blood clots that generally occur between four to 28 days after COVID-19 vaccination with an adenovirus-vector vaccine (the AstraZeneca and Johnson & Johnson vaccines).

These clots appear to occur in the setting of what is now being called “Vaccine-induced immune thrombotic thrombocytopenia (VITT).” However, blood clots are much more common with COVID-19 infection, than following COVID-19 vaccination.

Pfizer (Comirnaty) and Moderna (Spikevax) continue to be recommended for all people aged 12 years and above, while the AstraZeneca (Vaxzevria) vaccine is approved for use in people aged 18 years and over.

How important are booster shots?

A booster is an extra dose of the vaccine, that “boosts” the immune system and helps maintain a high level of protection from disease.

The latest research shows vaccine effectiveness wanes at around six months, so as more Australians hit that milestone, it will be increasingly important to receive a booster shot.

Booster shots are highly recommended to maintain immunity against COVID-19, and will ensure protection will be stronger, last longer and will help prevent the spread of the virus.

Read the Australian Government Department of Health's Advice on COVID-19 Booster Vaccines.

Women recieving a vaccine from a nurse

If I had side effects from my first vaccine schedule, should I still get a booster shot and if so, should I make sure it’s a different one from last time?

If you suffered from pericarditis with your earlier shots, you should discuss the booster with your doctor. However, if you experienced mild aches and pains or a bruised arm you should go ahead with the booster.

In Australia, the Pfizer (Comirnaty) vaccine is the available booster regardless of the earlier vaccine you had, although you can receive the AstraZeneca (Vaxzevria) vaccine in some circumstances.

When will children under the age of 12 be eligible for a vaccination?

In December 2021, Australia’s Therapeutic Goods Administration (TGA) provisionally approved the Pfizer COVID-19 vaccine for use in individuals five years and older.

This decision followed the provisional approvals granted by the TGA to Pfizer for the use of Pfizer (Comirnaty) in individuals 12 years and older in July 2021 and the booster dose for use in adults 18 years and older in October 2021.

After final approval from the Australian Technical Advisory Group on Immunisation (ATAGI), children aged five to 11 will be given two lower doses of the vaccine compared to those over 12, three weeks apart.

In clinical trials, the safety profile of the vaccine was similar to that seen with adults, with side effects observed to be mild. Most reported adverse events were pain and redness at the injection site, fatigue, headache, swelling, muscle pain and chills.

What more do we know about long COVID? You spoke with Dr David Putrino earlier in the year about his experience treating long COVID patients in New York. Have there been many reported cases in Australia and what are the symptoms to look out for?

Long COVID is a term for anybody who is having persistent symptoms after their initial COVID-19 infection. These symptoms include shortness of breath, fatigue, headaches, a loss of strength, lack of sleep and a loss of taste or smell. It can sometimes last weeks to months after recovery from the initial illness.

In October, a clinical case definition of long COVID was announced by the World Health Organisation (WHO), which they termed "Post COVID-19 condition".

The WHO said the condition "usually occurs three months from the onset of COVID-19 with symptoms [that] last for at least two months and cannot be explained by an alternative diagnosis”.

Meanwhile, data from the UK found one in three COVID-19 patients had long COVID three to six months after getting infected.

Australian data is yet to be released on the Delta strain. A recent study by Monash University that looked at COVID-19 patients in intensive care with the earlier strain of COVID-19 found nearly three-quarters of participants had lingering symptoms months after their recovery.


Visit our COVID-19 & Heart Disease Information Hub Watch the long COVID videoSupport our COVID-19 Research

Acknowledgement of Country

The Victor Chang Cardiac Research Institute acknowledges the traditional custodians of the land, the Gadigal of the Eora nation, on which we meet, work, and discover.
Our Western Australian laboratories pay their respect to the Whadjuk Noongar who remain as the spiritual and cultural custodians of their land.

Close