Results of three different vaccine trials released on Monday, all showed positive results with evidence that the vaccine boosted the immune response against the novel coronavirus.
All appeared safe, although more studies are required to show how safe they are against the infection.
The results of vaccine made by Pfizer and BioNTech were released in pre-print paper that had not yet been peer reviewed.
Oxford and AstraZeneca Trials:
The early results of the phase 1 and 2 of the the University of Oxford and AstraZeneca published in the The Lancet suggested that it is safe and induces an immune response.
The Oxford vaccine prompted an antibody response within 28 days and a T-cell response within 14 days, according to the results published. Neutralizing antibodies were detected in most participants after one shot, and in all of them after two.
“The immune system has two ways of finding and attacking pathogens, antibody and T cell responses. This vaccine is intended to induce both, so it can attack the virus when it’s circulating in the body, as well as attacking infected cells,” University of Oxford pediatrician Dr. Andrew Pollard said in a statement.
“We hope this means the immune system will remember the virus, so that our vaccine will protect people for an extended period. However, we need more research before we can confirm the vaccine effectively protects against SARS-CoV-2 infection, and for how long any protection lasts.”
It’s also not clear how well the vaccine would perform in older people who are more at risk of severe disease from Covid-19.
The vaccine trial included 1,077 people age 18 to 55 with no history of coronavirus infection and took place in five UK hospitals from late April to late May. Participants received the Covid-19 vaccine or a meningitis vaccine.
There were no serious adverse event related to the vaccine; fatigue and headache were the most commonly reported reactions. Other common side effects included pain at the injection site, muscle ache, malaise, chills, feeling feverish and high temperature.
Phase 1 and 2 trials of the Oxford vaccine showed promising results but large scale trials would actually determine how efficient it is against coronavirus.
CanSino Biologics Vaccine:
Phase 2 results published Monday suggested CanSino Biologics’ vaccine was safe and created an immune response. The trial, conducted in Wuhan, China, in April, involved more than 500 people given high, low or placebo doses of the vaccine, the release said.
The trial found that 95% of the participants in the high dosage group and 91% in the low dosage group showed either T-cell or antibody immune responses 28 days after vaccination. In the high dosage group, neutralizing antibody responses were induced in 59% and binding antibody responses in 96%. Binding antibodies attach to a virus but don’t stop it from infecting cells.
Half of people who got the low dose developed neutralizing antibodies.
Nine percent of the participants in the high-dose group had severe adverse reactions within 28 days, the most common of which was fever.
This vaccine uses a weakened human cold virus called an adenovirus to deliver genetic material mimicking coronavirus.
But questions remain about how long an immune response will last and how the vaccines will impact older populations, people with particular health conditions that put them at risk, and racial and ethnic groups more severely affected by Covid-19.
Pfizer and BioNTech Vaccine:
US pharmaceutical company Pfizer and German biotechnology company BioNTech reported their Covid-19 vaccine candidate elicited a “robust” antibody and T-cell immune responses in an early Phase 1/2 study.
The data has not yet been published in a peer-reviewed medical journal, but was published in a pre-print paper on Monday.
“The preliminary data indicate that our mRNA-based vaccine was able to stimulate antibody as well as T-cell responses at remarkably low dose levels,” Dr. Özlem Türeci, chief medical officer and co-founder of BioNTech said.
The German trial included 60 healthy adults ages 18 to 55 who were randomly assigned to receive varying doses of the vaccine.
The release also notes that there were some local reactions and mild to moderate adverse events, including some with flu-like symptoms and injection site reactions.
A phase 3 trial is expected in July end if regulatory approval is received.
There are 23 Covid-19 vaccines currently in clinical trials globally, according to the World Health Organisation.