'Very Low' Dose Moderna COVID-19 Vaccine Elicits Immune Response with No Side Effect, First Human Trial Show

Many experts believe that the only way to curb this pandemic is through herd immunity or if a vaccine is developed. Experts are now in a race to create the vaccine against the virus that causes COVID-19.

Drugmaker Moderna announced on Monday that it had developed a vaccine that appears to produce an immune response similar to the response seen in infected and recovered patients. During their Phase 1 trial, eight patients received two doses of the vaccine at the lowest and middle doses - 25 and 100 micrograms respectively.

They found that the patients have developed neutralizing antibodies to the virus with similar levels to those people who have recovered from the infection, according to the National Institute of Allergy and Infectious Diseases who led the trial.

Although the data is only limited, and from only a small number of participants in the trial, they are still likely to be seen as encouraging results. The research aimed to develop a vaccine against SARS showed that neutralizing antibodies are crucial for achieving protection.

Phase 1 Trial Shows Encouraging Results

Moderna's chief medical officer, Tal Zaks, said that "these interim Phase 1 data, while early, demonstrate that vaccination with mRNA-1273 elicits an immune response of the magnitude caused by natural infection starting with a dose as low as 25 μg,"

Moreover, the statement also included that a new arm of the trial is being established for a 50-microgram dose testing, which may imply that the 25-microgram dose may be too low.

But more than balancing the right dose, the researchers must also balance the need to achieve protection in high-risk individuals, such as the seniors whose immune systems do not respond very well to vaccines, with the goal to use as little vaccine as possible for every person to stretch out what will be limited supplies.

Zaks said in an interview with STAT, that although the 25 micrograms have shown encouraging results, it is still important to have somewhat of a margin. At the end of the day, the dose will be narrowed down between 25 and 100 micrograms.

Furthermore, Robin Robinson, chief scientific officer at RenovaCare, said that the neutralizing antibody and safety result from Phase 1 signals that Phase 2 can now commence. The company stated that vaccination from the candidate vaccine mRNA-1273 has also prevented viral replication in the lungs of the mice in a pre-clinical trial.

People in Phase 1 Well-Tolerated the Vaccine

The Food and Drug Administration has already given its signal to proceed to the Phase 2 trial. Additionally, a Phase 3 trial is set to begin in July and is ramping up its capacity to manufacture the vaccine to maximize the number of doses the company can produce to help protect as many people as possible, said CEO Stéphane Bancel.

According to Moderna's statement, the vaccine was well-tolerated by the people who have received it in the first phase. One participant has developed redness at the injection area upon receiving the 100-microgram dose of vaccine that met the criteria for a Grade 3 adverse event.

Furthermore, three of the volunteers have also developed Grade 3 systemic reactions after receiving the second of two doses of the highest dose of 250 micrograms. No Grade 4 or life-threatening adverse events recorded during the trial.

The early readout included three arms of the trial involving 45 people, ages 18 to 55 who either received two doses of 25 micrograms or 100 microgram level or one dose of 250 micrograms.

Those who received two doses of the 25 microgram level developed binding antibodies similar to the levels seen in people who recovered in COVID-19. On the other hand, people who received the 100 micrograms = had antibodies that significantly exceeded those seen in COVID-19 survivors.

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