Pfizer vaccine gives 95 per cent protection: Study
Largest real-world study from Israel confirms superior efficacy of two doses
PARIS: The largest real-world study yet of the Pfizer-BioNTech vaccine yesterday confirmed that it provided more than 95 per cent protection against Covid-19 but found the level dropped significantly when people received just one of the two prescribed doses.
Authors of the research from Israel's national vaccination campaign said it showed real-world proof that the pandemic could be ended by rapid, global vaccination programmes.
An analysis of public health data from Israel - one of the countries with the highest proportion of fully inoculated adults - showed the vaccine was extremely effective in protecting even elderly individuals at a time when the more infectious British variant was dominant, according to results published in the Lancet medical journal.
By the start of last month, nearly five million people in Israel had received two doses of the Pfizer-BioNTech jab, more than 70 per cent of the population.
The study found two doses conveyed 95.3 per cent protection against infection and 96.7 protection against death seven days after the second dose.
After 14 days, that protection increased to 96.5 per cent and 98 per cent, respectively.
But the protection was much lower when people received just a single vaccine dose.
Between seven and 14 days after the first dose, protection against infection was found to be 57.7 per cent and protection against death 77 per cent.
The authors said that one dose may provide a shorter window of protection, especially in an environment where new viral variants emerge.
"Importantly, the study shows that two doses of the vaccine significantly increase levels of immunity and protection," said professor of molecular virology at the University of Nottingham Jonathan Ball, who was part of the research.
"This is why it is important that people get both doses."
During the analysis period, there were 232,268 Covid-19 infections, and nearly 95 per cent of samples tested were found to be the British B117 variant. There were 4,481 severe infections and 1,113 deaths.
The team behind the research were not able to study the effect of the South African variant.
Meanwhile, the Covid-19 vaccine produced by China's Sinovac Biotech is effective in preventing Covid-19 in adults under 60, but some quality data on the risk of serious adverse effects is lacking, World Health Organisation (WHO) experts have found.
The independent experts on the WHO's Strategic Advisory Group of Experts reviewed Sinovac's CoronaVac jab from phase three clinical trials in China, Brazil, Indonesia, Turkey and Chile.
Although it was "very confident" that two doses of the vaccine are effective in preventing disease, it cited evidence gaps in safety in pregnancy, and on safety and clinical protection in older adults, those with underlying disease and evaluation of rare adverse events detected through post-authorisation safety monitoring. - AFP, REUTERS