What is currently known about myocarditis and the Comirnaty vaccine?

‘In April, reports of myocarditis being diagnosed in the few days following receipt of Comirnaty vaccine, particularly following the second dose, started to appear in countries using this vaccine in younger adults from 16 years (Israel and USA). ‘

In April, reports of myocarditis being diagnosed in the few days following receipt of Comirnaty vaccine, particularly following the second dose, started to appear in countries using this vaccine in younger adults from 16 years (Israel and USA). The vast majority of the cases of myocarditis reported to US CDC (to the end of May) following Comirinaty vaccination have been discharged from hospital (95%) with most fully recovered (81%). CDC is currently reviewing data from the Vaccine Safety Datalink network, which is able to directly compare rates of various conditions occurring with and without receipt of Comirinaty vaccine in large numbers of people, to evaluate the relative incidence and gather information about severity of myocarditis in vaccinated and unvaccinated young adults.  

Myocarditis and pericarditis are uncommon conditions, usually thought to be related to viral infection leading to inflammation of the heart muscle or the tissue surrounding the heart. Chest pain is the most common symptom. Diagnosis is based on elevated levels of cardiac enzymes in blood tests, and by electrocardiogram and echocardiogram tests. Rates of incidence vary between populations and by gender and age; for example, the incidence in adolescent males aged 14 to 18 years is significantly higher than in females. 

MedSafe is closely monitoring for any reports of myocarditis following COVID-19 vaccination in New Zealand. For further information please refer to the WHO’s statement.

Can I receive the COVID-19 vaccine even though I have a compromised immune system or am receiving treatment for cancer?

Many people take medication that suppresses their immune system, especially for the treatment of cancer, severe asthma, autoimmune diseases or following organ transplantation, or have medical conditions that can affect the immune system, such as HIV infection or kidney failure.

These conditions put you at increased risk from COVID-19, and although you may not respond as strongly to the vaccine as someone with a fully functioning immune system, it is safe for you received COVID-19 vaccine and it will provide some protection against COVID-19, particularly against severe and life-threatening disease.

It is important and safe for those receiving active treatment with immunosuppressive medications to have the COVID-19 vaccine. If you are severely immunocompromised, it is recommended to talk to your GP or specialist to discuss the optimal timing for vaccination before the vaccine appointment. Ideally, vaccination should be conducted prior to any planned immunosuppression.

It is also important for the people around you, in your household, to have the vaccine when it is offered to them to widen your protection.


For information about Cancer care and COVID-19 vaccine see Te Aho o Te Kahu (Cancer Control Agency) information here.

Can I delay receiving my second dose of Comirnaty?

It is recommended to have the second dose of Comirnaty™ at least 21 days after the first dose. A delay for longer than 21 days is not considered to be a problem in terms of how you will respond to the second dose.

It is not yet known, for how long the first dose provides protection. If you are at risk of exposure to SARS-CoV-2, it is advisable to have the second dose when recommended. During clinical trials, the vaccine efficacy against symptomatic COVID-19 between the first and second doses was around 50% compared with 90% within 2 days of the second dose increasing to 95% after a week. Recent real-world data has shown that protected against SARS-CoV-2 infection was around 62 to 91% from 14 days after dose one and 68 to 97 % from 14 days after dose two in frontline workers. 

Can I have the COVID-19 vaccine if I am allergic to latex?

Comirnaty™ is latex-free. The vial stopper is made with synthetic rubber (bromobutyl), not natural rubber latex.