I note the recent contributions in the Express, by Noel Kalicharan and Noble Philip, on the topic of vaccine efficacy and effectiveness.

Mr Kalicharan cited data from the clinical trials of various vaccines to challenge what he suggested might be widespread misconceptions about effectiveness of vaccines. He suggested that the results were based on “flimsy” and “minuscule” data and that the efficacy calculations from those trials were akin to “mathematical sleight-of-hand”.

As Mr Philip pointed out, the combined Moderna and Pfizer-BioNTech trials involved over 70,000 people and took place over several months. And the data emanating from these trials demonstrated statistically significant positive impacts of these vaccines— which is why the vaccines gained the approval from the regulatory agencies—who were advised by eminent scientists (and statisticians).

However, we do not have to rely only on the clinical trials. The real-world effectiveness of the vaccines has already been demonstrated. Mr Philip cited evidence from the USA, and I would like to point readers to three scientific studies of what happened when large numbers of people were vaccinated—one in Scotland, one in Israel and one in Brazil.

The Scottish study (Lancet 2021; 397: 1646–57; April 23, 2021; looked at a total of 1.3 million people vaccinated between December 2020 and February 2021, with either the Pfizer-BioNTech (mRNA) or the Oxford-AstraZeneca (AZ) vaccines. The average age of those vaccinated was 65 years. The first dose of the mRNA vaccine was associated with a vaccine effect of 91per cent for reduced Covid-19 hospital admission at 28–34 days post-vaccination; for the AZ vaccine it was 88 per cent. For those 80 and older, the vaccine effects against hospital admission due to Covid-19 were similar at 83 per cent.

The Israel study, also published in The Lancet (, included analysis of almost 155,000 Covid-19 infections in the January-April 2021 period, during which Israel was rapidly vaccinating its population with the Pfizer-BioNTech vaccine, administering more than ten million doses within four months. At seven days or longer after the second dose, the effectiveness results were:

• 95·3 per cent against SARS-CoV-2 infection,

• 91·5 per cent against asymptomatic SARS-CoV-2 infection,

• 97·0 per cent against symptomatic SARS-CoV-2 infection,

• 97·2 per cent against Covid19-related hospitalisation,

• 97·5 per cent against severe or critical Covid-19-related hospitalisation, and

• 96·7 per cent against Covid-19-re-lated deaths.

Furthermore, vaccine effectiveness against symptomatic SARS-CoV-2 infection, Covid-19-related hospitalisation, and Covid-19-related death exceeded 96 per cent across all age groups, including older adults (aged ≥75 years and ≥85 years).

These are properly-researched, peer-reviewed studies published in a respected medical journal. The Israeli study closely parallels, in a real-world setting, the efficacy results of the mRNA clinical trials, belying the claim that the statistical analysis was “mathematical sleight of hand”. And both studies demonstrated that the older age-groups —who may have been under-represented in the clinical trials—benefited significantly.

The smaller Brazilian study (referenced in analysed the effect of the Sinovac vaccine (which uses the same technology as the Sinopharm vaccine), in a controlled experiment in the town of Serrana, in which about 30,000 people, or two-thirds of the population, were vaccinated. The results were similar—deaths fell by 95 per cent in the five weeks right after the mass-vaccination was completed. Symptomatic cases dropped by 80 per cent and hospitalisations decreased by 86 per cent.

The studies cited above indicate that science has successfully addressed the challenge of developing an effective vaccine for Covid-19. The task at hand, that should be embraced by all right-thinking people, is to get these vaccines produced and administered to the bulk of the world’s population as rapidly as possible, so that the world can emerge from this devastating pandemic.

Krishendath Maharaj

adjunct lecturer,

Arthur Lok Jack Global

School of Business


This is a long overdue letter of thanks to the Public Health Department of the Division of Health, Wellness and Family Development of the THA.

We, the residents of Calder Hall Trace, Scarborough, have long enjoyed excellent service from the sanitation workers who operate in our neighbourhood.

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Each time I drive in the area, I marvel at the wanton waste of such an expensive resource, now a major eyesore.

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While much more needs to be done, the measures agreed on at Wednesday’s meeting between National Security Minister Fitzgerald Hinds and representatives of fishing organisations, the Police Service, the Coast Guard and the MP for Couva North should give fisherfolk some hope that the government is beginning to at least listen.

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