Helen Petousis Harris

Dr Helen Petousis-Harris blogs about vaccines and vaccination. Her background is predominantly biological sciences, and she did her PhD in Vaccinology, specifically around vaccine reactions. She worked at the Immunisation Advisory Centre at the University of Auckland between 1998 and 2018 where she has developed a passion for all things vaccine. Currently Helen has an appointment as an associate professor in the Department of General Practice and Primary Health Care and her teaching is largely around vaccination. Her research focuses on a number of aspects of vaccines and vaccination but in particular vaccine effectiveness and vaccine safety. She was previously the chair of the World Health Organization Global Advisory Committee on Vaccine Safety (GACVS). Of course all opinions in this blog are her own. Disclosures: Helen has led a number of industry funded studies. These have all been investigator conceived and led. She does not receive honorarium from industry personally. She has received industry support to attend some conferences and has contributed to Expert Advisory meetings for GSK, Merck, and Pfizer. Helen is a member of the Covid vaccine Science and Technical Advisory Group to MBIE and the MoH and the Covid Immunisation Implementation Advisory groups to the MoH.

Is injection technique contributing to the risk of post vaccine myocarditis? - Diplomatic Immunity

Oct 17, 2021

Recent misleading media headlines about vaccines being administered incorrectly in the absence of evidence do little to help public confidence in vaccines. Spoiler alert, vaccines are not being administered incorrectly. The topic of this blog is based on what could be an important scientific question – is one of the most widely used injection techniques a risk for serious vaccine reactions? Most vaccines are given by injection into muscle and techniques used to achieve this vary with a range of preferences. Over the past few months there has been a growing conversation about the way vaccines are injected and the potential for serious events, in this case, myocarditis. Myocarditis is inflammation of the heart muscle, and it can affect the way the heart performs. The most common cause is a viral infection, sometimes it might be a reaction to … Read More

Myocarditis as an adverse event following mRNA COVID-19 immunisation - Diplomatic Immunity

Aug 30, 2021

After hundreds of millions of doses away, the most rare side effects have revealed themselves. The one of concern involves inflammation of the heart. What is myocarditis? Myocarditis is an inflammation of the heart muscle; pericarditis is inflammation of the sac around the heart. Each year NZ has around 100 cases of myocarditis. A key trigger is a viral infection, including COVID-19. Symptoms include an abnormal heartbeat, new chest pain, and difficulty breathing. The condition can be severe and life threatening. Most cases will be admitted to hospital. Myocarditis and pericarditis following mRNA vaccines Q.  Is this a thing? A.  Yes. Q.  Should I be worried? A.  Not unduly, this is very rare, and most cases recover. You are much more likely to get myocarditis if you get COVID-19. In fact, struck by lightning is more likely … Read More

Fundamentally flawed study on COVID-19 vaccine safety is rapidly retracted - Diplomatic Immunity

Jul 03, 2021

The content of this blog has been adapted and expanded from comments I provided to Vaccines and Science this week. The perfectly respectable MDPI journal called Vaccines made a mistake but they addressed it fast. Somehow an article assessing vaccine safety and effectiveness that was fundamentally flawed and made outrageous claims slipped through the system. Not the first time something like this has happened nor will it be the last. The unmentionable mother of them all was published in the prestigious Lancet in 1998 and it took over a decade for a full retraction. This one took under a week (See Here for Retraction Watch). Below I discuss why this article should never have left the editorial office. During a time of unprecedented spread of misinformation and the challenges we face in immunising the global population against … Read More

Correcting propaganda containing 8 false claims about COVID-19 vaccines - Diplomatic Immunity

Apr 28, 2021

This is a short blog addressing a list of falsehoods being posted widely across Aotearoa New Zealand. The flyer (posted at the end) claims ‘8 important covid vaccine facts you probably haven’t heard’. Actually, these are 8 of the most common myths about Covid-19 vaccines. Some have been around so long they probably qualify as zombie myths. The ‘golden rules‘ of propaganda are used in the flyer – uses intense emotions, creates a dichotomy between “good” and “bad”, avoids data and rational discussion. #1 The COVID-19 vaccines that NZ has pre-purchase agreements for appear very safe. There have been some very rare blood-clotting events detected following administration of the viral-vector vaccines (Astra-Zeneca and Janssen) and these are being intensively investigated. Claims that suggest there are an alarming rate of deaths and serious injury caused by the … Read More

The Pfizer COVID-19 vaccine is way beyond experimental - Diplomatic Immunity

Apr 25, 2021

An experiment is a procedure carried out to test a hypothesis. We have determined through experiment, with extremely high precision, that the Pfizer COVID-19 works very well and is very safe. The initial experiments were successful, moving on… However, there are some misconceptions flying around that abuse this concept and I thought they needed addressing with some interpretation and facts. Hope this is helpful and clears up a few confusions. The most widely used COVID-19 vaccines are no longer ‘experimental’. One could argue that there are still experimental studies in play, for all of these vaccines, but then it is also the case for pretty much every vaccine I can think of. My group have been studying a vaccine that has been in wide use since the 1940s, among others. We never let up. Once a vaccine has been authorised … Read More

COVID vaccines and blood clots – what is this about? - Diplomatic Immunity

Apr 15, 2021

I will update this post as new information comes to hand What has happened? Recently the vaccine safety watch dogs in Europe noted reports of unusual types of blood clots in people vaccinated with the AstraZeneca (AZ) COVID-19 vaccine. This prompted investigations across many countries to ascertain what, why, and how. Also, in the last couple of days, the U.S. has reported unusual types of blood clots in people vaccinated with the Janssen/Johnson & Johnson COVID-19 vaccine. Observations so far suggest that in younger AZ vaccinees, primarily women, there might be an unusual type of blood disorder that involves both low platelets (that can lead to bleeding) and blood clotting at the same time (thrombocytopenia and thrombosis). This disorder is appearing a week or two after vaccine administration and has been given several names so far … Read More

COVID vaccine safety – adverse events vs. adverse reactions - Diplomatic Immunity

Apr 07, 2021

As we roll out the COVID-19 vaccine across NZ there will inevitably be people who experience adverse events after getting their jab. Here are some super important things to keep in mind about adverse events following immunisation. I will update this blog as we go along, latest 16 April. Terminology – words matter Any event that is undesirable and follows administration of a vaccine is called an adverse event following immunisation (AEFI). This is the term applied regardless of whether the vaccine was the cause of the event. An adverse reaction is, by definition, an adverse event that has been caused by the vaccine. This is a subgroup of all adverse events.   Some adverse reactions are obvious – a super sore arm or rash where the injection was given are pretty clearly reactions to the … Read More

COVID-19 vaccines and community immunity (transmission) - Diplomatic Immunity

Jan 22, 2021

Updated, 4 Feb 2021 to reflect new data on the AstraZeneca vaccine.  Q: Will the COVID-19 vaccines prevent the transmission of the coronavirus and bring about community immunity (aka herd immunity)? A: Jury not in yet but vaccines do not have to be perfect to thwart the spread of infection. While vaccines  induce protection against illness, they do not always stop actual infection, so you can be perfectly well but carry a deadly virus or bacteria and spread it to others. Typhoid Mary springs to mind, where in the nineteenth century Mary Mallon unknowingly infected at least 53 people with typhoid fever while perfectly well herself. Vaccines such as the HPV and measles vaccines prevent infection all together so vaccinated people do not transmit the infection, while other vaccines such as pertussis (whooping cough) prevent disease … Read More

The frail elderly and COVID vaccines – should we be concerned? - Unsorted

Jan 16, 2021

(updated 18 Jan to reflect new information) Health authorities in Norway are reporting some concerns about deaths in frail elderly after receiving their COVID-19 vaccine. Is this causally related to the vaccine? Probably not but here are the things to consider. According to the news there have been 23 29 deaths in Norway shortly after vaccine administration and apparently 13 autopsies had some kind of indication that common vaccine side effects might have contributed. We do not have information on these cases and I can’t imagine how an autopsy would reveal that a person died of a fever, muscle aches, fatigue, or a head ache (the common side effects). The more recent report states: Most people have experienced the expected side effects of the vaccine, such as nausea and vomiting, fever, local reactions at the … Read More

How good is the AstraZeneca vaccine looking? Look at the data, not news headlines - Diplomatic Immunity

Jan 15, 2021

Happy New Year! No, experts are not concerned that “…one of New Zealand’s COVID-19 vaccines will fail to protect the country” Here is why. But first I wish to issue an expletive about this journalism (First in Australia and then in NZ). It exhibits utter failure to actually truly consult the experts, other than a passing token quote. I call false journalistic balance. Grump out of the way, here is the story. A virology society in Australia issued a public statement about the AstraZeneca COVID-19 vaccine (AZ). They compared it to the Pfizer RNA vaccine and said it would not be good enough to achieve ‘herd immunity’ and Australia should halt deployment of it. They stated that the efficacy of the AstraZeneca vaccine was 62% and that the efficacy of the Pfizer vaccine was 95%. Oh boy … Read More