COVID-19: Even the 1st AZ vaccine dose cuts spread by 76%, says study

Virendra Pandit 

New Delhi: Amid reports of multiple strains of the global pandemic virus, COVID-19, emerging in different countries, a study on Wednesday revealed that even the first of the two-dose vaccine developed jointly by the University of Oxford and pharmaceutical major AstraZeneca can potentially cut the transmission by around 76 percent.

This reduction can have a “substantial effect” on controlling the spread of the deadly virus, according to a new Oxford University study, media reported.

Also, Oxford and AstraZeneca expect the ‘next generation’ COVID-19 vaccine to tackle the varients by autumn this year.

The British government has welcomed it as good news for the world because the impact of vaccines on transmission has been a crucial x-factor (unknown) in the struggle against the pandemic.

“The data indicate that (the vaccine) may have a substantial impact on transmission by reducing the number of infected individuals in the population,” the report said.

The Oxford Vaccine Trial results, currently under review to be published by the prestigious magazine ‘The Lancet’, also found that up to a three-month interval between the two required doses of the shot proved an effective gap as protection against the killer virus.

The Oxford-AstraZeneca vaccine is also being produced under license by the Serum Institute of India (SII), and is a major contributor to the ongoing vaccination drive, the largest of its kind globally, on January 16.

A single standard dose of this vaccine showed 76 percent efficacy from day 22 to day 90 after the jab. It means protection is not reduced in the three months between the first and second doses.

“This news about the Oxford vaccine is absolutely superb. Two-third reduction in transmission, stronger protection from the 12-week gap between doses, and no hospitalizations. This vaccine works and works well,” said UK Health Secretary Matt Hancock.

“The really good news embedded in it is that it does not just reduce hospitalizations there were no people in this part of the trial who are hospitalized with COVID after getting the Oxford jab but also it reduces the number of people who have COVID at all, even asymptomatically, by around two-thirds,” he said.

The study found that a single standard dose of the vaccine is 76 percent effective at protecting from primary symptomatic COVID-19 for the first 90 days post-vaccination, once the immune system has built this protection 22 days after the vaccination, with the protection showing little evidence of waning in this period.

“These new data provide an important verification of the interim data that was used by more than 25 regulators, including the MHRA and EMA, to grant the vaccine emergency use authorization,” said Professor Andrew Pollard, Chief Investigator and co-author of the Oxford Vaccine Trial.

“It also supports the policy recommendation made by the Joint Committee on Vaccination and Immunisation (JCVI) for a 12-week prime-boost interval, as they look for the optimal approach to roll out, and reassures us that people are protected from 22 days after a single dose of the vaccine,” he said.

The analysis, media reports said, based on swab tests on early recipients of the jabs, found no cases of hospitalizations and that the effect of dosing interval on efficacy is pronounced, with vaccine efficacy rising from 54.9 percent with an interval of fewer than six weeks to 82.4 percent when spaced 12 or more weeks apart. This supports the British government’s strategy of the mass rollout of the first doses, with a second dose after three months.

According to scientists, the findings are in line with previous research into other vaccines against diseases like influenza, Ebola, and malaria. The authors are hoping to report data regarding the vaccine’s impact on new COVID variants in the coming days as well.

The news comes as the National Health Service (NHS) says it has covered 9.6 million people in the UK with COVID first jabs, moving towards the government target of protecting all vulnerable groups by mid-February.

A related study also reveals that protective antibodies against COVID-19 last up to six months in most infected people. As many as 88 percent of people showed antibodies in their blood to fight COVID-19 six months after infection, the study based on the UK Biobank data of almost 1,700 people, revealed.