Friday , August 19 2022

Have Covid-19 vaccines been tested among older age groups?


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As we move closer to the release of a vaccine for Covid-19, people are anxious to know how well the vaccines that have been developed work and what groups of people they have been tested on.

There has been some discussion in Ireland in recent days about whether vaccines, such as those from Moderna, Pfizer and AstraZeneca, have been tested on groups of the elderly.

Speaking of Claire Byrne Live on RTÉ on Monday, November 30, Professor Sam McConkey said that most people who participate in vaccine trials are between 18 and 55 years old.

McConkey, an infectious disease specialist at the Royal College of Surgeons Ireland (RCSI), said that “if we had a vaccine that was 100% effective in preventing death in the elderly, in people over 80, over 90 and in the vulnerable, and also for to prevent transmission to other people that were publicly available then it would be really good ”.

“Unfortunately, in most Phase 3 studies, most people who sign up for them are young, healthy people between the ages of 18 and 55, so these vaccines probably work really well to prevent mild and moderate illness in young, healthy people between the ages of 18 and 18. to 55, but we know it’s not really the group that really suffers from Covid-19 death or serious illness, ”McConkey said.

Several vaccines have now undergone the three key phases of clinical trials and are looking to distribute them worldwide. During clinical trials, a number of factors are examined, including:

  • how well the vaccine protects against infection
  • the best dose
  • some side effects

Let’s take a look at three of the top vaccines from Moderna, Pfizer and AstraZeneca and the extent to which their clinical trials included people from older age groups.


The modern vaccine – mRNA-1273 – began its Phase 3 clinical trial in July, involving 30,000 adults at research sites in the United States.

Early results from the clinical trial showed that the vaccine, which Moderna hopes to have 20 million doses ready by the end of 2020 to be delivered in the United States, proved to be 94.5% effective.

The vaccine uses messenger RNA (mRNA), which means that the immune system is not exposed to the actual virus itself, but still triggers the production of antibodies in the immune system.

Modern is currently applying for approval of the vaccine from the US Food and Drug Administration (FDA) and the European Medicines Agency (EMA).

Eligibility requirements in the study included the need for participants to be 18 years of age or older and that they had not previously participated in a Covid-19 vaccine or treatment study.

Applicants needed to be healthy without a previous history of Covid-19, and if they had any pre-existing medical conditions, their conditions must be stable at the time of screening.

The study looked for participants who were at high risk for Covid-19 infection due to their location or circumstances, or at risk of becoming serious Covid-19 because they were over 65 years old or had an underlying medical condition.

Modern eligibility requirements

Source: Modern

Source: Modern / YouTube

More than 7,000 people over the age of 65 participated in phase 3 of Moderna’s clinical trial. Among the participants in Moderna’s vaccine phase 3 study:

  • 29% were between 25 and 44 years old
  • 39% were between 45 and 64 years old
  • and 25% were over 65 years of age.

By comparison, according to the UN Economic and Social Department, 9.3% of the world’s global population is over 65 years old.

This varies between regions – in high-income countries 18.4% of the population is over 65, 8.2% in middle-income countries and 3.3% in low-income countries.

Pfizer and BioNTech

The UK has formally approved the vaccine developed by Pfizer and BioNTech, which has been approved by the UK Medicines and Healthcare Products (MHRA) for emergency use.

The Pfizer vaccine has been shown to be 95% effective without any serious side effects in its clinical trials and has passed its safety controls.

Pfizer and BioNTech have said they plan to produce up to 50 million vaccines globally by 2020 and up to 1.3 billion by 2021.

In a statement, the UK Department of Health and Social Care said that after several months of “rigorous” clinical trials and data analysis, the MHRA concluded that the vaccine has met its strict requirements for safety, quality and efficacy.

“The Joint Committee on Vaccinations and Immunizations (JCVI) will soon publish its final advice to the priority groups receiving the vaccine, including nursing residents, carers, the elderly and the extremely vulnerable,” the department said.

The vaccine is expected to be available in the UK from next week.

The most recent clinical trial of the vaccine registered 43,931 participants, of whom 42,722 received the other of two vaccines.

The vaccine was studied at 150 clinical trials in the United States, Germany, Turkey, South Africa, Brazil and Argentina. Across the websites at the international level, 41% of the participants are between 56 and 85 years old.

In the United States, 45% of participants are in the same age group.

The effect of the vaccine was “consistent across age, gender, race and ethnicity demographics”.

The study observed an effect of over 94% in adults over 65 years.

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AstraZeneca (Oxford)

The AstraZeneca vaccine, developed at the University of Oxford, has been clinically tested under two different dosing regimens.

The first tested regimen, which involved a halved first dose and a standard dose, was found to have 90% efficacy.

The second dosing system, which administered two full doses, had 62% efficacy.

In a study on the safety and immunogenicity (ability to elicit an immune response) of the vaccine during the second phase of the trials involving 560 participants:

  • 160 were between 18 and 55 years old
  • 160 were between 56 and 69 years old
  • and 240 were 70 years of age or older.

The side effects of the vaccine decreased as age increased, with fewer side effects reported in the older age groups than among 18- to 55-year-olds.

The study showed that antibody reactions in the two older age groups “were comparable to those seen in younger adults”.

“Similarly, antibody levels increased after a second dose of the vaccine, and this was also consistent for the older age groups.”

The study states that “further assessment of the effect of this vaccine is justified in all age groups and individuals with comorbidity” and that more consideration is especially justified for those living in care environments or over 80 years.

“Larger studies are now underway to assess the immunogenicity, safety and efficacy of older adults with a wider range of comorbidities.”

In the latest clinical trials of the vaccine, which registered 24,000 participants from the UK, Brazil and South Africa, the University of Oxford stated that the Phase III interim data “are based on Oxford’s Phase I / II peer-reviewed test results which have shown that the vaccine induces strong antibodies and T-cell immune responses in all age groups, including older adults, and has a good safety profile ”.

Basically, Covid-19 vaccines such as those from Moderna, Pfizer and AstraZeneca have been tested among older age groups, and the elderly have shown large proportions in each vaccine’s clinical trials.

For the two with whom data have been shared – Pfizer and AstraZeneca – the effect of the vaccines among the elderly has been in line with the results on a broader scale. Ongoing studies of the vaccines continue.

The next step in clinical testing – phase four – will involve follow-up with the participants in the coming years.’s FactCheck is a signatory to the International Fact-Checking Network’s Principles. You can read it here. For information on how FactCheck works, what the judges mean and how you can participate, check out our reader guide here. You can read about the team of editors and reporters who work with the fact checks here.

Applicants need to be healthy with no previous history of Covid-19, and if they have pre-existing medical conditions, their condition must be stable.

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