By Helen Petousis Harris 25/04/2021


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 for wide use we do not consider it is ‘experimental’, even though scientists will use it experimentally for practically ever. As of writing over 1 billion people have received a COVID-19 vaccine and the Pfizer version has quite a lion’s share of this.

Scientists are watching these vaccines like a bunch of anxious hawks and that is how we picked up extremely rare safety signals associated with the viral vector vaccines. The fact that events as rare as a few per million can be picked up and investigated should reassure people just how sensitive the safety surveillance systems are.

Now we have effective vaccines we have moved into the post-marketing phase. This is where we determine the effectiveness in the real world and scan for very rare side effects. This is done for all routine vaccines, not just COVID-19 vaccines.

The vaccines were developed fast, but not recklessly

The science behind these vaccines is not completely new. The plug-and-play platforms such as the viral-vectors and mRNA were already available and had already been tested in humans. All that needed to happen to prepare a vaccine candidate for human trials was to plug in the instructions to make the SARS-CoV-2 spike protein. The technology was ready and waiting. Human data was available for all of these vaccine platforms, including previous coronaviruses such as MERS and SARS.

Getting a vaccine through a series of human trials to assess efficacy and safety has traditionally taken some years. This is for the following reasons:

  • Money – the process costs in the order of billions and if the product does not work or there is not a big enough market then it will be a financial disaster
  • Reliance on Big Pharma – Relying on big pharma to fund financially risky adventures such as vaccine development left us vulnerable but no one else would do it.
  • Recruiting participants to studies – It can take years to recruit sufficient participants into a vaccine trial.
  • Accruing enough events in a vaccine trial to demonstrate that the vaccine works
  • Regulatory agencies weighed down with bureaucracy that move at a snail’s pace.

These obstacles were first overcome a few years ago in order to get an Ebola vaccine to Africa so COVID-19 is not the first example of this kind of speed. The Ebola vaccine candidates were sitting ready to go on a shelf so when push finally came to shove the clinical studies were completed within a year. Saying that vaccines normally take years is very true, and that is a bad thing not a good thing. Our traditional model was terrible, and it has cost many lives over the years.

Speed, not haste, is saving many lives.

COVID-19 vaccines are saving many lives

The impact expected from COVID-19 vaccines has been modelled all over the world by many groups for example Imperial College and University of Texas. The argument is not whether or not the vaccines save lives but rather how to roll them out to maximum effect.

The vaccines are also extremely cost effective. There have been some assessments about the cost-benefits of potential COVID-19 vaccines published, for example this one from Canada. It has been estimated that equitable access to COVID-19 vaccines will save nearly half a trillion to 10 major economies. However cost-benefit is only one factor considered when deciding to fund a medicine. What about Herceptin for example?

Clinical trials for vaccines can run for the life of the vaccine – decades.

In order for a vaccine to receive authorisation for use the regulators want enough data on safety and efficacy to approve for wider use. In this case they wanted to see a vaccine that protected at least half the people who received it from disease and did not induce side effects of concern in the study population. This means they wanted safety data that extended at least two months because pretty much all vaccine related adverse events will occur within this time frame. Clinical trials have a number of endpoints, not all are needed for authorisation, particularly when the product is desperately needed.

Does it work and is it safe? Essentially these are what are called Primary Endpoints – the main results. The study must be big enough to determine these with a high level of certainty.

Secondary endpoints in vaccine trials might include things like antibody levels two or three years in the future or other disease outcomes.

If the vaccine proves to be effective and the control participants are at high risk of disease then it becomes unethical to leave the control group unprotected so they will usually be be offered the treatment.

The vaccine has been assessed and approved by Medsafe

Medsafe are our regulatory agency, and their job is to ensure the safety of all medicines and medical devices used in New Zealand. They are there to protect the population against harm from medicines.

While agencies in countries under COVID-19 siege gave emergency use approval for these vaccines, New Zealand had the luxury of putting the vaccines through the full approval process. As COVID-19 is currently a pandemic disease, and the situation is evolving rapidly, the vaccine has been given provisional approval. Medsafe have asked the manufacturer to provide ongoing information about the vaccine, this is normal. For example, if there are any changes to the manufacturing processes or site of manufacture, Medsafe want to know the details. This does not mean that the vaccine is unsafe. If the vaccine was not very safe then Medsafe would not authorise its use. It is as simple as that.

This is a public health emergency of mammoth proportion

There can be no doubt that COIVD-19 represents a global public health emergency. While there may be examples of difficulties interpreting excess deaths the horrific situation seen in India and Brazil, and previously seen in the UK and Italy, with crushed health systems, dispair, and mass burials, surely represents a burden of human suffering most would deem unacceptable. Protecting only the elderly because they are more likely to die makes no sense as deaths and severe disease occur to some extent across all age groups, and all humans serve to spread the infection. If we do not vaccinate most of the community then this damn plague will continue to circulate, therefore, all age groups must be vaccinated or we will be living this nightmare for years to come.