COVID-19: Expert explains what treatments are being used on Omicron patients and how effective they are

  • 16/03/2022
On Wednesday there were 971 people in hospital with COVID-19.
On Wednesday there were 971 people in hospital with COVID-19. Photo credit: Getty Images

With New Zealand's increasing COVID-19 hospitalisations and steepening death curve, people are wondering how are COVID patients are treated.

Intensive care specialist at the Auckland City Hospital Dr Colin McArthur explains the treatments used against the virus.

Dr McArthur says there are two broad areas of treatment - those directed against the virus itself (antivirals) and those that modify the body's response to the infection (immune modulators).

He says antiviral treatments need to be given within five to seven days of symptoms beginning, while immune-modulating treatment is only for patients who are hospitalised and need breathing support.

Antiviral treatments in New Zealand include the drug remdesivir which is used for patients in hospital within the first seven days, Dr McArthur says.

"It is also effective at reducing the risk of hospitalisation in those at high risk, but early administration of an intravenous drug outside of hospital is difficult," he says.

"Processes are being established now to provide this treatment in the community for those at the greatest risk of deterioration, as supplies are limited."

Another treatment is oral antiviral agents that need to commence within five days of symptoms beginning to work, therefore, making early diagnosis of COVID important.

"The oral antiviral agents, Paxlovid (a combination of nirmatrelvir and ritonavir) and molnupiravir, are also of benefit to those at higher risk of hospitalisation, and are expected to be available over the next few months."

Another treatment aimed at the virus is monoclonal antibodies, which help the body identify and eliminate the virus. 

"We have supplies of Ronapreve (a combination of casirivimab and imdevimab) in New Zealand currently, but unfortunately although this is effective against earlier variants such as Delta, it is not active against Omicron.

"Some monoclonal antibodies such as sotrovimab do retain activity against Omicron, but these are understandably in high demand globally and are not yet available here. These treatments are also given by injection and their use pre-hospital where they are most effective has similar challenges to remdesivir."

What happens in hospital?

On Wednesday there were 971 people in hospital with COVID-19 and a total of 141 people have died while infected with the virus - these figures are expected to continue to climb.

Dr McArthur says treatment in hospital for COVID depends on a patient's severity and rate of progression.

"Once there is a sustained need for additional oxygen, immune-modulating treatment is begun, initially steroid treatment with dexamethasone," he says.

If there is further deterioration, a drug that blocks parts of the inflammatory response is used, using either drug tocilizumab or barcitininb.

"As lung function worsens, higher flows of oxygen are provided," Dr McArthur says.

"Additional assistance with breathing can be given with a sealed mask to provide additional support, and in some severe cases mechanical ventilation - via a tube into the lungs - may be required."

He says treatment also includes low doses of blood-thinning treatment because the virus can cause blood clots and when there is evidence of lung inflammation intense blood therapy may be used.

But how effective are the treatments?

Dr McArthur says COVID treatments were studied before Omicron came on the scene, so it is unknown if Omicron will impact the effectiveness of the current treatments.

"This is a known issue for the monoclonal antibodies, many of which are less effective because they were designed to attach to the original SARS-CoV-2 spike protein," he says. 

"We also know that Omicron is a less severe variant and so treatments given to reduce the risk of severe disease need to be highly-targeted to those at the very highest risk to be beneficial."

However, Dr McArthur says it is less likely other treatments will lose effectiveness.