Covid-19 vaccine has better immune response with two full-dose regime, claims Oxford
Oxford University on Thursday said that its COVID-19 vaccine candidate has a better immune response when a two full-dose regime is used rather than a full-dose followed by a half-dose booster, Reuters reported. Oxford's vaccine candidate, licensed to AstraZeneca, has published interim late stage trial results showing higher efficacy when a half dose is followed by a full dose, compared to a two full-dose regime, though more work needs to be done to affirm the result.
On Thursday, details from the Phase I/II clinical trials were released, which made no reference to the half-dose/full-dose regime, that Oxford has said had been "unplanned" but approved by regulators. The university said it had explored two dosing regimes in early stage trials, a full-dose/full-dose regime and a full-dose/half-dose regime, investigated as a possible "dose sparing" strategy.
"The booster doses of the vaccine are both shown to induce stronger antibody responses than a single dose, the standard dose/standard dose inducing the best response," the university said in a statement.
The vaccine "stimulates broad antibody and T cell functions," it said further.
Earlier, researchers from the University of Oxford and pharmaceutical major AstraZeneca presented a pooled analysis of phase 3 trials of their vaccine against COVID-19 across two different dose regimens, which showed that the vaccine is safe and has an average efficacy of 70.4 per cent.
When the interim trial results were made public in a press release last month, the researchers reported three efficacy levels for the vaccine – an overall effectiveness of 70 per cent, a lower one of 62 per cent and a high of 90 per cent -- due to different doses of the vaccine being mistakenly used in one part of the trial.
The Oxford University and AstraZeneca COVID-19 vaccine, currently awaiting regulatory approvals, is set to be used for a “mix and match” trial with Russia’s Sputnik vaccine against the novel coronavirus.
Meanwhile, AstraZeneca Country President Gagandeep Singh said that Oxford-AstraZeneca's vaccine can be available in India as early as the first half of 2021. Pune-based Serum Institute of India is conducting clinical trials of Oxford University-AstraZeneca's COVID-19 vaccine candidate Covishield in India.
According to Singh, the vaccine can be stored, transported and handled at comfortable refrigerated conditions (2 to 8 degrees) which is very comfortable to handle, meaning it can be administered very rapidly across the country.
