263 views | Akanimo Sampson | July 22, 2020
A major step is underway towards a COVID-19 vaccine that is effective and safe for widespread use.
This is so because two coronavirus vaccine candidates have proven safe for humans and produced strong immune reactions among patients involved in separate clinical trials, doctors say.
The first trial involved more than 1,000 adults in Britain and the second in China more than 500 people.
While this is published in The Lancet medical journal, British biotech firm Synairgen says a randomised trial of an aerosol-based treatment shows it could drastically reduce the number of new coronavirus patients dying from the disease or requiring intensive care.
This is coming as Nigeria on Tuesday recorded four COVID-19 deaths which automatically raised the national death toll to 805.
Nigeria Centre for Disease Control (NCDC) has also announced 576 fresh COVID-19 cases in the country, pointing out, ‘’till date, 37801 cases have been confirmed, 15677 cases have been discharged and 805 deaths have been recorded in 36 states and the Federal Capital Territory, Abuja.’’
Of the 576 new cases from 22 states of the federation, Lagos returned to the number one slot after two days break with 88 cases. Kwara follows with 87, Abuja 82, Plateau 62, Ondo 39, Enugu 28, Oyo 26, Taraba 24, Kaduna 20, Ebonyi 20, Edo 17, Cross River 16, Kano 14, Rivers 11, Ogun 10, Delta nine, Nasarawa eight, Osun eight, Katsina three, Imo two, Kebbi and Borno one each.
In the meantime, the World Health Organisation (WHO) voices alarm at the spread of COVID-19 in Africa, warning South Africa’s surging numbers could be a “precursor” for outbreaks across the continent.
Until recently, Africa had remained relatively unscathed by the pandemic, but the situation has become increasingly worrying, particularly in South Africa, which has passed the 5,000-death mark.
More than 606,600 dead
The pandemic has killed at least 606,605 people worldwide since it surfaced in China late last year, according to an AFP tally at 1100 GMT on Monday based on official sources. The United States has the most deaths with 140,534, followed by Brazil with 79,488, Britain with 45,300, Mexico with 39,184, and Italy with 35,045.
Russia, the world’s fourth hardest-hit country in terms of infections, reports fewer than 6,000 new cases for the first time since the end of April.
“The situation is improving,” President Vladimir Putin says during a visit to Crimea, noting other countries are seeing a “flare-up” in cases.
The cricket T20 World Cup due to take place in Australia from October 18 has been postponed until next year due to the pandemic, the International Cricket Council announces. A new date is being pencilled in from October to November 2021.
EU seeks to break summit deadlock
European Union chief Charles Michel puts forward a new proposal for a massive, but scaled-down, a coronavirus rescue plan for the recession-battered bloc, in hopes of breaking four days of deadlock at a summit in Brussels.
“I think an agreement is possible,” Michel says of his proposal aimed at bridging the divide between frugal EU countries like the Netherlands and Austria and the worst pandemic-hit—and most indebted—members such as Italy and Spain.
However, scientists have uncovered how a crucial component of the immune system responds to the spike protein of SARS-CoV-2, the virus that causes COVID-19—important information for future validation of vaccine candidates.
Coronavirus particles have a corona (crown) of proteins that resemble spikes, which enable the virus to attach and enter cells in humans.
The spike protein is crucial in inducing neutralizing antibodies to protect from re-infection.
This is coming as an investigational vaccine, mRNA-1273, designed to protect against SARS-CoV-2, the virus that causes coronavirus disease 2019 (COVID-19), was generally well tolerated and prompted neutralising antibody activity in healthy adults, according to interim results published online today in The New England Journal of Medicine.
The ongoing Phase 1 trial is supported by the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health.
The experimental vaccine is being co-developed by researchers at NIAID and at Moderna, Inc. of Cambridge, Massachusetts.
Manufactured by Moderna, mRNA-1273 is designed to induce neutralizing antibodies directed at a portion of the coronavirus “spike” protein, which the virus uses to bind to and enter human cells.
The trial was led by Lisa A. Jackson, M.D., MPH, of Kaiser Permanente Washington Health Research Institute in Seattle, where the first participant received the candidate vaccine on March 16. This interim report details the initial findings from the first 45 participants ages 18 to 55 years enrolled at the study sites in Seattle and at Emory University in Atlanta.
Three groups of 15 participants received two intramuscular injections, 28 days apart, of either 25, 100 or 250 micrograms (mcg) of the investigational vaccine. All the participants received one injection; 42 received both scheduled injections.
In April, the trial was expanded to enrol adults older than age 55 years; it now has 120 participants. However, the newly published results cover the 18 to 55-year age group only.
Regarding safety, no serious adverse events were reported. More than half of the participants reported fatigue, headache, chills, myalgia or pain at the injection site. Systemic adverse events were more common following the second vaccination and in those who received the highest vaccine dose.
Data on side effects and immune responses at various vaccine dosages informed the doses used or planned for use in Phase 2 and 3 clinical trials of the investigational vaccine.
The interim analysis includes results of tests measuring levels of vaccine-induced neutralizing activity through day 43 after the second injection.
Two doses of vaccine prompted high levels of neutralizing antibody activity that were above the average values seen in convalescent sera obtained from persons with confirmed COVID-19 disease.
A Phase 2 clinical trial of mRNA-1273, sponsored by Moderna, began enrollment in late May. Plans are underway to launch a Phase 3 efficacy trial in July 2020.
However, neutralising antibodies not only bind to the viral spike protein but prevent it from being able to attach to and enter human cells. Generating a strong neutralizing antibody response is an important goal for SARS-CoV-2 vaccines.
The spike protein is the target for most of the current COVID-19 vaccine human clinical trials and so a team from the Peter Doherty Institute for Infection and Immunity (Doherty Institute) was keen to investigate how the immune system, particularly B and T cells, respond to the spike.
B cells are responsible for producing the antibodies that recognize SARS-CoV-2, while T cells play an important role in supporting the development of the B cell response.
University of Melbourne Dr. Jennifer Juno, a postdoctoral researcher at the Doherty Institute, said they looked at people who had recovered from COVID-19 who had mostly experienced mild or no symptoms, as that kind of immune response mimics what a vaccine might induce.
“We found that those who showed strong neutralizing antibody activity had a robust B cell response, but most surprisingly, we also found that a particular subset of T cells, called T-follicular helper cells, was a great predictor of an effective immune response,” Dr. Juno said.
“We have previously demonstrated through influenza research that B cells are key to mounting an effective immune response to influenza, and we also know that T-follicular helper cells specifically help B cells to make antibodies.”
The research team hopes the ‘immune parameters’ they’ve identified and published today in Nature Medicine can be applied to clinical vaccine trials to assess whether or not a vaccine might induce a strong or weak neutralizing antibody response.
“Now we know how the immune system responds to the spike protein, and we have these biomarkers, or predictors of what elicits a good or poor immune response to COVID-19, we can look at the vaccine candidates and see what will offer the best protection,” Dr. Juno explained.
In addition to COVID-19, the researchers also looked at circulating coronaviruses that cause the common cold in an effort to understand what would predict the neutralizing response to SARS-CoV-2.
These findings were consistent with what was described in the immune responses of other people who had recovered from COVID-19.