NZ Herald
  • Home
  • Latest news
  • Herald NOW
  • Video
  • New Zealand
  • Sport
  • World
  • Business
  • Entertainment
  • Podcasts
  • Quizzes
  • Opinion
  • Lifestyle
  • Travel
  • Viva
  • Weather

Subscriptions

  • Herald Premium
  • Viva Premium
  • The Listener
  • BusinessDesk

Sections

  • Latest news
  • New Zealand
    • All New Zealand
    • Crime
    • Politics
    • Education
    • Open Justice
    • Scam Update
  • Herald NOW
  • On The Up
  • World
    • All World
    • Australia
    • Asia
    • UK
    • United States
    • Middle East
    • Europe
    • Pacific
  • Business
    • All Business
    • MarketsSharesCurrencyCommoditiesStock TakesCrypto
    • Markets with Madison
    • Media Insider
    • Business analysis
    • Personal financeKiwiSaverInterest ratesTaxInvestment
    • EconomyInflationGDPOfficial cash rateEmployment
    • Small business
    • Business reportsMood of the BoardroomProject AucklandSustainable business and financeCapital markets reportAgribusiness reportInfrastructure reportDynamic business
    • Deloitte Top 200 Awards
    • CompaniesAged CareAgribusinessAirlinesBanking and financeConstructionEnergyFreight and logisticsHealthcareManufacturingMedia and MarketingRetailTelecommunicationsTourism
  • Opinion
    • All Opinion
    • Analysis
    • Editorials
    • Business analysis
    • Premium opinion
    • Letters to the editor
  • Politics
  • Sport
    • All Sport
    • OlympicsParalympics
    • RugbySuper RugbyNPCAll BlacksBlack FernsRugby sevensSchool rugby
    • CricketBlack CapsWhite Ferns
    • Racing
    • NetballSilver Ferns
    • LeagueWarriorsNRL
    • FootballWellington PhoenixAuckland FCAll WhitesFootball FernsEnglish Premier League
    • GolfNZ Open
    • MotorsportFormula 1
    • Boxing
    • UFC
    • BasketballNBABreakersTall BlacksTall Ferns
    • Tennis
    • Cycling
    • Athletics
    • SailingAmerica's CupSailGP
    • Rowing
  • Lifestyle
    • All Lifestyle
    • Viva - Food, fashion & beauty
    • Society Insider
    • Royals
    • Sex & relationships
    • Food & drinkRecipesRecipe collectionsRestaurant reviewsRestaurant bookings
    • Health & wellbeing
    • Fashion & beauty
    • Pets & animals
    • The Selection - Shop the trendsShop fashionShop beautyShop entertainmentShop giftsShop home & living
    • Milford's Investing Place
  • Entertainment
    • All Entertainment
    • TV
    • MoviesMovie reviews
    • MusicMusic reviews
    • BooksBook reviews
    • Culture
    • ReviewsBook reviewsMovie reviewsMusic reviewsRestaurant reviews
  • Travel
    • All Travel
    • News
    • New ZealandNorthlandAucklandWellingtonCanterburyOtago / QueenstownNelson-TasmanBest NZ beaches
    • International travelAustraliaPacific IslandsEuropeUKUSAAfricaAsia
    • Rail holidays
    • Cruise holidays
    • Ski holidays
    • Luxury travel
    • Adventure travel
  • Kāhu Māori news
  • Environment
    • All Environment
    • Our Green Future
  • Talanoa Pacific news
  • Property
    • All Property
    • Property Insider
    • Interest rates tracker
    • Residential property listings
    • Commercial property listings
  • Health
  • Technology
    • All Technology
    • AI
    • Social media
  • Rural
    • All Rural
    • Dairy farming
    • Sheep & beef farming
    • Horticulture
    • Animal health
    • Rural business
    • Rural life
    • Rural technology
    • Opinion
    • Audio & podcasts
  • Weather forecasts
    • All Weather forecasts
    • Kaitaia
    • Whangārei
    • Dargaville
    • Auckland
    • Thames
    • Tauranga
    • Hamilton
    • Whakatāne
    • Rotorua
    • Tokoroa
    • Te Kuiti
    • Taumaranui
    • Taupō
    • Gisborne
    • New Plymouth
    • Napier
    • Hastings
    • Dannevirke
    • Whanganui
    • Palmerston North
    • Levin
    • Paraparaumu
    • Masterton
    • Wellington
    • Motueka
    • Nelson
    • Blenheim
    • Westport
    • Reefton
    • Kaikōura
    • Greymouth
    • Hokitika
    • Christchurch
    • Ashburton
    • Timaru
    • Wānaka
    • Oamaru
    • Queenstown
    • Dunedin
    • Gore
    • Invercargill
  • Meet the journalists
  • Promotions & competitions
  • OneRoof property listings
  • Driven car news

Puzzles & Quizzes

  • Puzzles
    • All Puzzles
    • Sudoku
    • Code Cracker
    • Crosswords
    • Cryptic crossword
    • Wordsearch
  • Quizzes
    • All Quizzes
    • Morning quiz
    • Afternoon quiz
    • Sports quiz

Regions

  • Northland
    • All Northland
    • Far North
    • Kaitaia
    • Kerikeri
    • Kaikohe
    • Bay of Islands
    • Whangarei
    • Dargaville
    • Kaipara
    • Mangawhai
  • Auckland
  • Waikato
    • All Waikato
    • Hamilton
    • Coromandel & Hauraki
    • Matamata & Piako
    • Cambridge
    • Te Awamutu
    • Tokoroa & South Waikato
    • Taupō & Tūrangi
  • Bay of Plenty
    • All Bay of Plenty
    • Katikati
    • Tauranga
    • Mount Maunganui
    • Pāpāmoa
    • Te Puke
    • Whakatāne
  • Rotorua
  • Hawke's Bay
    • All Hawke's Bay
    • Napier
    • Hastings
    • Havelock North
    • Central Hawke's Bay
    • Wairoa
  • Taranaki
    • All Taranaki
    • Stratford
    • New Plymouth
    • Hāwera
  • Manawatū - Whanganui
    • All Manawatū - Whanganui
    • Whanganui
    • Palmerston North
    • Manawatū
    • Tararua
    • Horowhenua
  • Wellington
    • All Wellington
    • Kapiti
    • Wairarapa
    • Upper Hutt
    • Lower Hutt
  • Nelson & Tasman
    • All Nelson & Tasman
    • Motueka
    • Nelson
    • Tasman
  • Marlborough
  • West Coast
  • Canterbury
    • All Canterbury
    • Kaikōura
    • Christchurch
    • Ashburton
    • Timaru
  • Otago
    • All Otago
    • Oamaru
    • Dunedin
    • Balclutha
    • Alexandra
    • Queenstown
    • Wanaka
  • Southland
    • All Southland
    • Invercargill
    • Gore
    • Stewart Island
  • Gisborne

Media

  • Video
    • All Video
    • NZ news video
    • Herald NOW
    • Business news video
    • Politics news video
    • Sport video
    • World news video
    • Lifestyle video
    • Entertainment video
    • Travel video
    • Markets with Madison
    • Kea Kids news
  • Podcasts
    • All Podcasts
    • The Front Page
    • On the Tiles
    • Ask me Anything
    • The Little Things
  • Cartoons
  • Photo galleries
  • Today's Paper - E-editions
  • Photo sales
  • Classifieds

NZME Network

  • Advertise with NZME
  • OneRoof
  • Driven Car Guide
  • BusinessDesk
  • Newstalk ZB
  • Sunlive
  • ZM
  • The Hits
  • Coast
  • Radio Hauraki
  • The Alternative Commentary Collective
  • Gold
  • Flava
  • iHeart Radio
  • Hokonui
  • Radio Wanaka
  • iHeartCountry New Zealand
  • Restaurant Hub
  • NZME Events

SubscribeSign In
Advertisement
Advertise with NZME.
Home / New Zealand

Covid 19: How common are severe side effects from Covid vaccines? And how are they detected?

Other
22 Dec, 2022 08:10 PM7 mins to read

Subscribe to listen

Access to Herald Premium articles require a Premium subscription. Subscribe now to listen.
Already a subscriber?  Sign in here

Listening to articles is free for open-access content—explore other articles or learn more about text-to-speech.
‌
Save

    Share this article

A nurse gives a Pfizer Covid-19 vaccine shot. Photo / AP

A nurse gives a Pfizer Covid-19 vaccine shot. Photo / AP

Opinion

Former Australian federal MP Dr Kerryn Phelps has talked this week about the medical problems she and her wife had after their Covid-19 vaccinations around 18 months ago.

In her submission to the parliamentary inquiry into long Covid, Phelps said her wife Jackie Stricker-Phelps had ongoing neurological problems after her first vaccine. Phelps herself experienced breathlessness and blood-pressure fluctuations after her second dose.

Dr Kerryn Phelps has revealed that she and her wife Jackie Stricker-Phelps have suffered severe adverse reactions to the COVID vaccine.

Dr Phelps calls for more research into the side effects of the vaccine and the long-term harm of the virus. #Studio10 pic.twitter.com/xZzTpTHf5p

— Studio 10 (@Studio10au) December 21, 2022

This has prompted public discussion about severe side effects, known as “adverse events”, after Covid-19 vaccines.

We’re vaccine experts and while we can’t specifically comment on Phelps’ concerns, here’s how adverse events are tracked, confirmed and prevented.

Advertisement
Advertise with NZME.
Advertisement
Advertise with NZME.

Understanding new health concerns

In any new large vaccine rollout, some people will experience a serious medical problem in the period after the new vaccine is given, and wonder “was it from the vaccine?”.

This is particularly the case when the problem has an uncertain cause, is not well understood or is only recently described. People naturally want to know the cause of a problem.

Good vaccine safety systems address these questions. The condition occurring in a window of time after vaccination is an obvious criterion. But other factors are crucial when determining whether one thing caused another.

It’s important to consider these other factors, because not everything that happens after a vaccine is due to the vaccine. Heart attacks, strokes, new autoimmune diseases, and death can all occur shortly after a vaccine. The key question is whether a vaccine caused or worsened the risk of a condition.

Advertisement
Advertise with NZME.

Tracking new adverse events

Strong vaccine safety systems are designed to identify and investigate potential new health issues related to a vaccine.

Safety assessments start early in product development then proceed to clinical trial assessments. Clinical trials, including for Covid-19 vaccines, compare a group who receive the vaccine with another receiving a placebo (or another vaccine).

These trials are large – around 20,000-30,000 people are closely monitored for many months – but can only detect relatively common side effects.

More than 13 billion Covid-19 vaccine doses have been given globally. As vaccines are given to the wider population, many countries (including Australia) monitor for rare and serious side effects.

Safety monitoring has occurred across the whole populations in more than 190 countries. Detailed epidemiological studies have also included many millions of people. These studies look at whether the risk of a condition is increased in people shortly after vaccination, compared to other times or in unvaccinated people.

More than 13 billion Covid-19 vaccine doses have been given globally. Photo / Facebook / Government of Samoa
More than 13 billion Covid-19 vaccine doses have been given globally. Photo / Facebook / Government of Samoa

So what have they found?

Some rare but serious events caused by Covid-19 vaccines were detected within months of the vaccine rollout.

Thrombosis with thrombocytopenia syndrome is a serious but rare clotting disorder. It occurs in around one in 50,000 doses of the AstraZeneca Covid-19 vaccine, with 173 cases reported in Australia. This was rapidly reported and its detection shaped the Covid-19 vaccine rollout.

Myocarditis (inflammation of the heart muscle) has been seen more frequently, particularly in teenage boys and young men after mRNA vaccines (around two to ten cases for every 100,000 second Pfizer Covid-19 vaccine doses). While most people with myocarditis related to vaccine have mild symptoms and recover over days or weeks, a small number have more serious disease or prolonged symptoms.

Other rare conditions related to Covid-19 vaccines include anaphylaxis, Guillain-Barré syndrome and immune thrombocytopenia. However, the risk for these events is lower than the serious risks from Covid-19 itself in the absence of vaccination.

There are many “signals” or suggestions that other conditions are linked to Covid-19 vaccines. A recent study, for example, suggests a common syndrome call postural orthostatic tachycardia syndrome (POTS) occurred after vaccination but was five times more common after Covid-19 itself. However, as the authors of the study pointed out, further studies are needed.

Advertisement
Advertise with NZME.

Other signals have not been substantiated by evidence at all.

The WHO Global Advisory Committee on Vaccine Safety releases regular statements as any new vaccine safety signals are investigated and confirmed.

So how does Australia track vaccine problems?

Australia monitors and assesses vaccine safety through the Therapeutic Goods Administration (TGA) and health departments, with close involvement of independent vaccine safety scientists and a range of clinical experts, by:

1) Asking clinicians and patients to report any adverse event after vaccination to the TGA

The TGA examines many severe adverse events in detail, sometimes through an expert panel. Others are tracked and classified to see if they’re being reported at unusually high rates.

The TGA has processed more than 136,000 reports for Covid-19 vaccines up to mid-November 2022. Not all reports represent events caused by the vaccine but reporting helps identify unusual patterns, including by comparing rates of a condition after vaccination to that seen usually in the population without vaccines (the background rate).

Advertisement
Advertise with NZME.

The TGA acknowledges receipt of reports but does not routinely give feedback on individual cases. In some cases, the person reporting is contacted if further information is required to either complete or assess the adverse event report.

2) Using active surveillance systems including AusVaxSafety

Researchers survey millions of people at regular intervals after vaccination to look for new signals and publish fortnightly real-time reports.

These reports and peer-reviewed studies show Covid-19 vaccines have a very good safety profile, including in people with a range of pre-existing medical conditions. These people benefit most from vaccination as they are at the highest risk of complications from Covid-19.

Women wearing face masks line up for their routine Covid-19 tests in Beijing. Photo /
Women wearing face masks line up for their routine Covid-19 tests in Beijing. Photo /

3) Monitoring for conditions that could theoretically be a risk after vaccination

This occurs in all phases of vaccine development, clinical trials and program rollouts, often using specially designed studies and long-term follow-up.

Advertisement
Advertise with NZME.

4) Getting information and safety reports from other countries, multinational groups and vaccine manufacturers

This is done continuously. Thrombosis with thrombocytopenia syndrome (the rare clotting disorder), for example, was first reported in Europe and myocarditis in Israel.

5) Looking at studies using large electronic health databases to check for positive or negative links between vaccination and health conditions

These types of studies showed no link between measles, mumps and rubella vaccines and autism. They must take into account many factors, such as Covid-19 itself.

A recent Danish study, yet to be peer-reviewed, for example, showed fewer new health problems four months after Omicron infection in people given a booster compared to those given only two doses of the Covid-19 vaccine.

6) Using a national network of specialist clinicians to support GPs and specialists to assess patients with complex immunisation questions

Advertisement
Advertise with NZME.

This includes questions about health conditions before or after vaccines, and how to approach additional vaccine doses.

What if you have an adverse effect after vaccination?

The first thing to do is report it. Either patients or clinicians can report adverse events to the TGA.

Second, ensure your health care is managed by a GP and/or specialist who can investigate all possible causes, and seek expert support as needed.

When rare adverse events are shown to be caused by a vaccine, people should be compensated.

In August 2021, the Australian government announced a scheme to support individuals suffering from serious health conditions caused by a Covid-19 vaccination, joining many other countries in doing so.

Advertisement
Advertise with NZME.

Despite the slow implementation, no-fault vaccine compensation is a key component of a comprehensive vaccine safety program. We recommend ensuring this scheme is optimised and also includes all vaccines, not just those for Covid-19.

Transparency is essential

It’s important to have open and evidence-informed discussions about the benefits and risks of vaccination – both for Covid-19 and other vaccine-preventable diseases.

Vaccines are clearly life-saving. A recent study estimated there were 20 million fewer deaths in the first year of a rollout thanks to Covid-19 vaccines.

However, a key to achieving high coverage is confidence, which requires transparency about vaccine safety, as well as factual and empathic communication.

· Kristine Macartney - Professor, Discipline of Paediatrics and Child Health, University of Sydney · Allen Cheng - Professor in Infectious Diseases Epidemiology, Monash University · Christopher Blyth - Paediatrician, Infectious Diseases Physician and Clinical Microbiologist, Telethon Kids Institute, The University of Western Australia · Julie Leask - Professor, Susan Wakil School of Nursing and Midwifery, University of Sydney

Save

    Share this article

Latest from New Zealand

New Zealand

Lawyer challenges 'plain wrong decision' in Jago's sexual abuse case

17 Jun 09:20 AM
New Zealand

Watch: Inside look after fire engulfs Auckland supermarket

17 Jun 08:15 AM
New Zealand|crime

Fit of rage: Man injures seven people in attack on partner, kids and neighbours

17 Jun 08:00 AM

Jono and Ben brew up a tea-fuelled adventure in Sri Lanka

sponsored
Advertisement
Advertise with NZME.

Latest from New Zealand

Lawyer challenges 'plain wrong decision' in Jago's sexual abuse case

Lawyer challenges 'plain wrong decision' in Jago's sexual abuse case

17 Jun 09:20 AM

Former Act president's lawyer claims sentence was too harsh, calls for home detention.

Watch: Inside look after fire engulfs Auckland supermarket

Watch: Inside look after fire engulfs Auckland supermarket

17 Jun 08:15 AM
Fit of rage: Man injures seven people in attack on partner, kids and neighbours

Fit of rage: Man injures seven people in attack on partner, kids and neighbours

17 Jun 08:00 AM
Inside look: Damage revealed after fire engulfs Auckland supermarket

Inside look: Damage revealed after fire engulfs Auckland supermarket

Help for those helping hardest-hit
sponsored

Help for those helping hardest-hit

NZ Herald
  • About NZ Herald
  • Meet the journalists
  • Newsletters
  • Classifieds
  • Help & support
  • Contact us
  • House rules
  • Privacy Policy
  • Terms of use
  • Competition terms & conditions
  • Our use of AI
Subscriber Services
  • NZ Herald e-editions
  • Daily puzzles & quizzes
  • Manage your digital subscription
  • Manage your print subscription
  • Subscribe to the NZ Herald newspaper
  • Subscribe to Herald Premium
  • Gift a subscription
  • Subscriber FAQs
  • Subscription terms & conditions
  • Promotions and subscriber benefits
NZME Network
  • The New Zealand Herald
  • The Northland Age
  • The Northern Advocate
  • Waikato Herald
  • Bay of Plenty Times
  • Rotorua Daily Post
  • Hawke's Bay Today
  • Whanganui Chronicle
  • Viva
  • NZ Listener
  • Newstalk ZB
  • BusinessDesk
  • OneRoof
  • Driven Car Guide
  • iHeart Radio
  • Restaurant Hub
NZME
  • About NZME
  • NZME careers
  • Advertise with NZME
  • Digital self-service advertising
  • Book your classified ad
  • Photo sales
  • NZME Events
  • © Copyright 2025 NZME Publishing Limited
TOP