Scientists around the globe are using different technologies to develop a vaccine that can fight the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that has disrupted life as we know it. The efforts of the researchers are still in process as no drug has been introduced yet that can beat the novel virus.
The investigational drug for COVID-19, known as ‘mRNA-1273’, has recently entered its phase III trial. The scientists from the National Institute of Allergy and Infectious Diseases (NIAID), a part of the National Institutes of Health (NIH), did an experiment on rhesus macaques by injecting two doses of mRNA-1273 that showed positive outcomes by reversing the infection caused by COVID-19. The findings of the current experiment have been published at The New England Journal of Medicine (NEMJ).
— NEJM (@NEJM) July 28, 2020
News: Experimental COVID-19 vaccine protects upper and lower airways in nonhuman primates https://t.co/BTiiVHRC8p
— NIH (@NIH) July 28, 2020
The researchers from NIAID experimented by injecting the new investigational drug on non-human primates to check the immune response. The non-human primates included rhesus macaques that were infected with the deadly coronavirus that has plunged the world into a crisis as no other virus did ever before. COVID-19 has affected more than 16.7 million people throughout the world with more than 661,000 mortalities whereas the virus has impacted the United States of America on a destructive level by taking above 149,000 lives. More than 4.3 million infected cases are still running into the country, according to data compiled by Coronavirus Resource Center: Johns Hopkins University (CRC-JHU).
To see the changes in the immune system and upper and lower airways of non-human primates, the team collected data of eight rhesus macaques. They divided the data into three groups and injected doses of mRNA-1273 that was co-developed by scientists at the NIAID Vaccine Research Center and at Moderna, Inc., Cambridge, Massachusetts.
We’re excited to announce the start of a phase 3 clinical trial of investigational vaccine mRNA-1273 for #COVID19, co-developed by @NIAIDNews and @Moderna. It will assess safety and preventive power, enrolling 30k+ volunteers over the next 3 months https://t.co/r1Li3GhSw3
— NIH (@NIH) July 27, 2020
The first and second group received a 10 mg and 100 mg dose of mRNA-1273, respectively. The third or the placebo group received the treatment which is specifically designed to have no real effect. The team injected the animals after every 28 days.
The results showed that the rhesus macaques produced high levels of neutralizing antibodies directed at the surface spike protein used by SARS-CoV-2. Spike protein is a major surface protein that acts as a doorway into a human cell. This protein allows the genome of the virus to enter into the human cells to spread infection.
The investigators from NIAID said: “Animals receiving the 10-µg or 100-µg dose vaccine candidate produced neutralizing antibodies in the blood at levels well above those found in people who recovered from COVID-19”.
Experimental Drug-Induced Th1 and Th2 Responses
The team also determined that the investigational drug also induce Th1 T-cell response that can be defined as T-helper type 1 cytokines that produce the proinflammatory responses responsible for killing intracellular parasites and bacterial pathogens. The drug did not induce Th2 T-cell response which is also involved in the anti-inflammatory response. The induction of Th2 responses was linked with a phenomenon called vaccine-associated enhancement of respiratory disease (VAERD).
On another hand, the researchers have also found that VAERD was not linked with other respiratory illnesses in responses to Th1 T-cell.
Another finding of the current study suggested that mRNA1273 has also produce T follicular helper cells that are located in the human tonsils. T follicular helper cells play a critical role in protective immunity by helping B cells to produce antibody against foreign viral or bacterial pathogens.
Findings of Infected Lungs: Four weeks after the second injection, the team determined that seven out of eight animals from the first and second groups were found to be virus-free from the lungs right after two days of injecting the second dose.
Findings of Infected Nose: All of the eight macaques became virus free from the nose after two days of injecting the second dose
Findings from Placebo: All the animals from the placebo group remained infected with the novel coronavirus in the lung.
The present study is the first of its kind on animals that showed a speedy control over the deadly virus from the upper airways.
The experts added: “A COVID-19 vaccine that reduces viral replication in the lungs would limit disease in the individual while reducing shedding in the upper airway would potentially lessen the transmission of SARS-CoV-2 and consequently reduce the spread of disease”.