• AstraZeneca and Oxford University vaccine trial paused due to possible adverse reaction.
  • New study compares severe COVID-19 reaction in children to Kawasaki’s disease.

Vaccine trial on hold due to possible adverse reaction

Phase III clinical trials for the coronavirus vaccine developed by AstraZeneca and Oxford University, have been paused after a participant involved in the trial had a suspected adverse reaction.

The New York Times reports that a volunteer in the UK trial has been diagnosed with transverse myelitis, an inflammatory syndrome that affects the spinal cord and can be caused by viral infections. However, the cause of the illness has not been confirmed and an independent investigation will now work out if the reaction was linked to the vaccine or not.

Following successful Phase I and II clinical trials earlier this year, the AZ-Oxford vaccine moved into final stage (Phase III) testing in recent weeks, involving some 30,000 participants in the US, UK, Brazil and South Africa.

There are currently nine vaccine candidates in Phase III trials. The AZ-Oxford vaccine is considered a front-runner, with late-stage clinical trials under way around the world, with hopes to have a vaccine ready before the end of the year.

The vaccine uses an adenovirus that carries a gene for one of the proteins in SARS-CoV-2, the virus that causes Covid-19. The adenovirus is designed to trigger the immune system to generate a protective response against SARS-2.

In a statement, AstraZeneca described the trial’s halt, as a “routine action which has to happen whenever there is a potentially unexplained illness in one of the trials, while it is investigated, ensuring we maintain the integrity of the trials.”

The company said it was “working to expedite the review of the single event to minimize any potential impact on the trial timeline,” and reaffirmed its commitment “to the safety of our participants and the highest standards of conduct in our trials.”

Children with severe COVID-19 reaction show unique immune profile

Although COVID-19 is mild in most children, several hundred children worldwide have reportedly developed severe hyperinflammatory disorders one to two months after infection that have led to multiple organ failure, and even death in some cases.

Scientists at the Karolinska Institute in Stockholm are now trying to figure out the biology of this rare and devastating condition, called multisystem inflammatory syndrome in children (MIS-C).

To understand MIS-C’s biological profile, they looked at 13 children with MIS-C, 28 children with Kawasaki’s disease (which shares overlapping features with MIS-C) and 41 with mild COVID-19. The researchers reported that compared with children with Kawasaki’s disease, those with MIS-C have lower levels of an immune chemical called IL-17A, which has been implicated in inflammation and autoimmune disorders.

New cases of COVID-19 worldwide from January 23 to September 10, 2020, by day Published by John Elflein, Sep 11, 2020  On September 10, 2020, there were 271,256 new cases of coronavirus (COVID-19) worldwide. The total number of cases has reached almost 28 million, with around 914 thousand deaths. Countries start to ease lockdowns Lockdowns around the world have helped to slow the spread of new infections – restrictions include working from home, limiting public gatherings, and banning all non-essential travel. However, the easing of some measures has led to concerns of a second wave of infections. Countries are being urged to continue widespread testing, and experts have warned that some measures, such as social distancing and the wearing of face masks in public, may stay in place for the foreseeable future. Plans to increase testing are stepped up For many countries, widespread testing is an essential part of any plan to reopen society. Rapid diagnostic tests (RDT) are increasingly being used to detect infection in patients. One type of RDT analyzes a sample to look for antigens – molecules found on the SARS-CoV-2 coronavirus – but the more common type of RDT tests for the presence of antibodies. The detection of antibodies in a blood sample means the body has been exposed to the virus, and immune system cells have reacted by producing antibodies to fight it. Mass testing is a strategy used to quickly identify areas with high cases, making it easier to isolate groups and prevent the spread. Read more Number of new cases of coronavirus (COVID-19) worldwide from January 23 to September 10, 2020, by day
New cases of COVID-19 worldwide from 23 January to 10 September
Image: Statista

Unlike all the other children studied, children with MIS-C had no antibodies to two coronaviruses that cause the common cold. It is possible that this deficit might be implicated in the origins of their condition.

More research is needed, with a larger number of children, to further understand the reasons why some children have mild COVID-19, and others go on to develop MIS-C.