AstraZeneca’s COVID-19 vaccine is thought to be one of the biggest game changers when it comes to getting a handle on the pandemic.
Unlike some other vaccines, AstraZeneca’s vaccine, which is given in two doses a month apart, doesn’t need to be stored in super-cold temperatures.
Each dose is significantly cheaper than the other shots and will be easier to distribute to rural areas and developing countries.
Recently, AstraZeneca announced its vaccine is about 70 percent effective at preventing COVID-19.
But a closer look at the clinical trials shows the efficacy isn’t as clear-cut as the pharmaceutical initially stated.
During the clinical trials, some participants were mistakenly given half a dose rather than a full dose in their first round of shots, according to BBC News. Still, the trial continued and the researchers discovered those given the weaker dosage produced a better immune response.
Here’s what experts make of AstraZeneca’s vaccine trials.
The error led to an important discovery
When regulators were informed of the mistake — that nearly 3,000 participants had received a lower dose — they permitted the trial to continue, as the dosing error had no impact on the vaccine’s safety.
In fact, the dosing mistake led to an interesting discovery.
In the participants who received two full doses, the vaccine efficacy was 62 percent. But in those who received a half dose and a full dose, efficacy was close to 90 percent.
“It’s a happy coincidence that they sort of stumbled onto a way that seems to be a better way for the human immune system to receive that particle vaccine, process it, and prepare for a longer-lasting immunity,” said Dr. Matthew Heinz, a hospitalist based in Tucson, Arizona, noting that the findings aren’t yet conclusive.
Averaged together, AstraZeneca announced via a press release its vaccine is 70 percent effective at preventing COVID-19.
The researchers are investigating why the weaker dose produced a more robust immune response.
How does the error impact the trial?
Some experts have criticized the fact that AstraZeneca combined the efficacy results from what’s essentially two different trials and say the company will need to conduct another trial properly evaluating the effectiveness of the half-dose full-dose regimen.
“Small mistakes are common, but giving thousands of participants the wrong dose unintentionally is not a common mistake. Time will tell whether this particular mistake leads to a discovery, but at this point in time there is a lot of uncertainty around the findings,” said Dr. Philip Smith, an assistant professor in the department of kinesiology and health at Miami University in Ohio.
Smith, whose research focuses on public health and health policy, believes AstraZeneca will seek approval for the full dose, which is 62 percent effective.
The big question is whether regulators will trust the 62 percent, considering the sample size was smaller than intended, said Smith.
AstraZeneca plans to publish the full, final findings in a medical journal. Regulators who approve the vaccine will have access to this data and will make the final call if the evidence is sufficient.
ResultsTrusted Source from a phase 2 study previously published in The Lancet showed the full two-dose vaccine produced a strong immune response in participants of all ages.
“Publishing the full report will hopefully help clarify the situation so that a broad scientific community of experts can weigh in based on complete information,” Smith said.