Coronavirus infection triggers inflammation as the body tries to fight it off. But sometimes the immune system goes into overdrive, which can prove fatal, attacking the body's own cells as well as the infection.
Town said in New Zealand treatments for this had included dexamethasone and tocilizumab, given to patients with severe reactions and in ICU, and it had proven effective.
A third being used in hospitals was remdesivir, an anti-viral drug shown to help those recovering from Covid-19 to improve the speed of their recovery and reduce the spread of the virus in the lungs.
This week Pharmac announced it had secured 60,000 doses of a new antiviral drug from Pfizer, which is known overseas as Paxlovid.
Trials have been very promising for the oral pill, with the risk of hospitalisation reducing by 89 per cent for adults with mild to moderate Covid-19 at high risk of progressing to severe illness when administered within days of diagnosis.
The drug adds to five other medications secured by Pharmac specifically to treat Covid-19, including baricitinib, ronapreve, remdesivir, tocilizumab, and another antiviral pill molnupiravir.
Money for all six medicines comes from the Government's Covid-19 fund.
The two antiviral pills could be taken in oral form, meaning they could potentially be prescribed by a doctor and picked up at a local pharmacy said Sarah Fitt, head of government drug-buying agency Pharmac.
Her team was working on how that could function in practice, given infected people needed to quarantine, and in particular how it would work in isolated regions as the drugs needed to be prescribed no more than five days after symptoms.
Ultimately the best approach was vaccination, but this would help those who were unvaccinated, immunocompromised, and/or the most vulnerable, she said.
Bloomfield said despite these drugs offering greater protections, it was "hard to overstate" how important being vaccinated was.
Even the vaccine for influenza was only 40 to 60 per cent effective.
"So to have a vaccine developed so impressively quickly with efficacy against hospitalisation and death well over 90 per cent is incredible news."
Bloomfield said it was also promising this week to see Pfizer's study showing the vaccine effective against Omicron once a booster had been taken.
The effects of combining the vaccine with proper treatments was seen in New Zealand's death rate this year, Bloomfield said.
Even though there were close to 10,000 cases, fewer people had died in this outbreak than last year, which was also because of a younger demographic, he said.
Since the start of the pandemic scientists have been trialling a huge range of these drugs, with limited degrees of success until now.
However, while stocks have been secured many are yet to be approved here by Medsafe - New Zealand's medicines and medical devices safety authority.
Supplies of ronapreve for example had been secured in September and molnupiravir in October but had still not been approved by Medsafe, which is required to measure just the effectiveness but also any potential side effects.
The United States government has ordered 10 million courses of the drug for US$5.3 billion, though the Food and Drug Administration (FDA) is still working through its authorisation process.
The Pfizer antiviral is expected to be delivered to New Zealand in April, once approved by Medsafe.
Bloomfield said Medsafe was working as fast as it could, but it was often held up in receiving the necessary data from drug companies.
These have been developed quickly and with small population testing, so it was important for Medsafe to maintain its "rigour" in approval process, he said.
"We are not cutting any corners."
This often meant Medsafe needed to go back to the companies for data.
"We are at the behest of manufacturers, but that does not mean we are waiting, we are in active discussion."
Alongside vaccinations, treatments were reducing the likelihood of people needing ICU care, with the ICU rate in Auckland dropping to 3 per cent of hospitalisations, down from 5.7 per cent previously, the ministry has reported.
New Zealand's Covid-19 treatments
There are a range of treatments being used in New Zealand's Covid-19 response. Some are medicines that existed before but have been shown to be effective in treating Covid-19, while others have only recently been developed and are still undergoing testing.
Some have been approved by MedSafe, while others that are unapproved for Covid-19 can only be used under certain circumstances under section 25 of the Medicines Act.
Dexamethasone
A type of corticosteroid that reduces, or "dampens", inflammation and immune system activity. It has been used to treat arthritis. Approved for use here to treat Covid-19 in those aged over 12. There have been moderate to high benefits to people with severe or critical Covid-19 who require oxygen, such as in ICU.
Budesonide
Budesonide is an inhaled corticosteroid, commonly called Pulmicort inhalers, approved here as a preventative treatment for asthma and for treatment of chronic obstructive pulmonary disease. It may reduce the need for Covid-19-related urgent medical care and improve recovery time in people in a community setting.
Tocilizumab
Tocilizumab is a mono-clonal antibody, a more target-specific type of anti-inflammatory medicine, and is approved in Aotearoa as a treatment of auto-immune conditions, such as rheumatoid arthritis. It is administered intravenously (by IV drip). Tocilizumab has been shown to slightly reduce mortality at day 28 among patients with severe Covid-19.
It has been approved by Medsafe for use in New Zealand, but not to treat Covid-19, although Pharmac has expanded its funded access to include use for Covid-19. There have been global shortages of the drug, however, after its increased usage because of Covid-19, and the supplier cancelled New Zealand's orders to January.
Remdesivir
One of the best known treatments so far is remdesivir, an antiviral drug that has been used overseas and in New Zealand to try and stop the Covid-19 virus from replicating and spreading in the body. Remdesivir is intravenously administered and made by Gilead, which originally developed it for hepatitis C. It has also been used for Ebola.
Pharmac has secured additional stock specifically for treatment of Covid, but while it has been approved by Medsafe for use in New Zealand, it has not yet been approved to treat Covid-19.
Molnupiravir
This antiviral pill is to be taken twice a day. It works by introducing errors into the genetic code of the virus. It has been approved by the United States' Food and Drug Administration (FDA), in a narrow decision.
Initial trials showed the drug reduced risk of hospitalisation or death by about 50 percent compared to a placebo. However in the final analysis of the trial, the drug's effectiveness dropped to 30 per cent.
New Zealand secured a deal for the supply of the drug in early October, but this is conditional on Medsafe approval.
Ritonovir (Paxlovid overseas)
Pfizer's new Covid-19 antiviral pill is similar to molnupiravir but requires three pills to be taken twice a day for five days.
Studies showed it reduced the risk of hospitalisation and death by about 89 per cent for people treated within three days of symptoms, and 85 per cent for those within five days.
Pharmac has secured 60,000 doses but it is yet to be approved by MedSafe. This is expected to occur by April.
Ronapreve
Ronapreve, produced by Roche, belongs to a class of medicines called monoclonal antibodies, or mAbs. They mimic the natural antibodies that the immune system makes to fight disease. Pharmac has secured enough Ronapreve to treat 5300 people, with "medium-to-severe" symptoms. MedSafe is still assessing the application.
Baricitinib
Baricitinib, an oral tablet, is used to treat moderate to severe cases of Covid-19. Pharmac has approved funding for about 500 courses from November 5, but the drug is not yet approved by Medsafe.