Published: 27 November 2020
Revised 11 April 2022


Medicines to treat COVID-19 – Questions and Answers

This page provides some commonly asked questions about Medsafe’s regulatory role in approving medicines used for the COVID-19 pandemic. More information about COVID-19 is available on the Ministry of Health website.

Which COVID-19 treatments are approved for use in New Zealand?

Several medicines are now approved for the treatment of COVID-19.

Medicine Approved indication
Dexmethsone (dexamethasone) Treatment of coronavirus disease 2019 (COVID-19) in adult and adolescent patients (aged 12 years and older with body weight at least 40 kg) who require supplemental oxygen therapy.
Ronapreve (casirivimab and imdevimab) Treatment Treatment of COVID-19 in adults and adolescents (aged 12 years and older and weighing at least 40 kg) who do not require supplemental oxygen for COVID-19 and who are at increased risk of progressing to severe COVID-19.

Post-exposure prophylaxis Prevention of COVID-19 in adults and adolescents (aged 12 years and older and weighing at least 40 kg) who have been exposed to SARS-CoV-2 AND who either:
  • have a medical condition making them unlikely to respond to or be protected by vaccination, or
  • are not vaccinated against COVID-19.
Ronapreve is not intended to be used as a substitute for vaccination against COVID-19.
Paxlovid (nirmatrelvir and ritonavir) Treatment of coronavirus disease 2019 (COVID-19) in adults 18 years of age and older, who do not require initiation of supplemental oxygen due to COVID-19 and are at increased risk of progression to hospitalisation or death.

The data sheets and consumer medicine information leaflets for these medicines are available on our website.

The approval status of other COVID-19 treatment applications received by Medsafe is also available.

Can hydroxychloroquine or ivermectin be used to treat COVID-19?

Ivermectin is not approved in New Zealand (or in other OECD countries) to prevent or treat COVID-19 disease in humans. Medsafe has not received any applications for approval of these medicines for treatment of COVID-19. Refer to the medicine’s data sheet for the approved indications.

See the following links for more information on ivermectin and COVID-19:

Will COVID-19 therapeutics work against new variants of the virus?

Some therapeutics that target the SARS-CoV-2 S-protein, such as Ronapreve1, are not effective against the omicron variant of the virus.

Since changes in the S-protein result in new variants, targeting other parts of the virus may mean that the medicine remains effective against new variants. Other COVID-19 therapeutics, such as Paxlovid2, that target other proteins in the virus should remain effective against new variants.

Paxlovid contains nirmatrelvir and ritonavir. Nirmatrelvir inhibits the SARS-CoV-2 main protease (Mpro), also known as 3C-like protease (3CLpro). Inhibition of Mpro prevents the virus from replicating. Ritonavir inhibits the metabolism of nirmatrelvir, thereby increasing plasma concentrations of nirmatrelvir2,3.

In addition, Mpro is an essential component of viral replication. Significant mutations in this protein are likely to mean that the virus cannot replicate and therefore cannot form a new variant.

Can Paxlovid be used in vaccinated individuals, even though vaccinated individuals weren’t included in the clinical trial (study C4671005)?

Yes, Paxlovid can be used in vaccinated individuals, even though they were excluded from the clinical trial.

COVID-19 vaccination has been demonstrated to significantly reduce the incidence of hospitalisation and death due to COVID-19. Vaccinated participants were excluded from the Paxlovid clinical trial (study C4671005; also called EPIC-HR). This is consistent with studies of other COVID-19 therapies. By only including unvaccinated participants, these studies could be conducted faster as they needed to include fewer people to show that the medicine works. Including vaccinated subjects would have significantly delayed this medicine from being available to help prevent death in people infected with COVID-19.

The Paxlovid clinical trial C4671005 was a phase 2/3 randomised, placebo-controlled trial in 2,246 non-hospitalised symptomatic adult participants with a laboratory-confirmed diagnosis of SARS-CoV-2 infection. Eligible participants had at least one risk factor for progression to severe disease2,3.

Some vaccinated people can still have poor outcomes, and continued vaccine efficacy against all variants of COVID-19 is not guaranteed. Waning immunity to COVID-19 vaccination and breakthrough infections are serious concerns, particularly in individuals at risk for severe illness from COVID-19.

Because Paxlovid targets a different part of the virus to vaccines (described above), no differences in efficacy are expected in vaccinated and unvaccinated individuals who become infected with SARS-CoV-2 and are treated with Paxlovid.

  1. Roche Products (New Zealand) Limited. 2022. Ronapreve New Zealand Data Sheet 21 February 2022. URL: (accessed 8 April 2022).
  2. Hammond J, Leister-Tebbe H, Gardner A, et al. 2022. Oral nirmatrelvir for high-risk, nonhospitalized adults with COVID-19. New England Journal of Medicine Feb 16: NEJMoa2118542. DOI: 10.1056/NEJMoa2118542 (accessed 7 April 2022).
  3. Pfizer New Zealand Limited. 2022. Paxlovid New Zealand Data Sheet 2 March 2022. URL: (accessed 7 April 2022).
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