WEDNESDAY, Sept. 9, 2020 (Healthday News) -- Final testing of a leading coronavirus vaccine candidate was paused by drugmaker AstraZeneca on Tuesday after a trial volunteer experienced a serious adverse reaction.
The company did not release specifics on the case, and whether the reaction was caused by the vaccine or was coincidental is still unclear, The New York Times reported.
The pause, first reported by STAT, will allow for a safety review and investigation of what caused the illness.
The disappointing news came as drug companies around the world race to develop a coronavirus vaccine that could bring an end to an international pandemic that has claimed almost 900,000 lives, the Times reported.
AstraZeneca's vaccine is a front-runner, with late-stage clinical trials underway in different countries. If the cause of the reaction turns out to be related to the vaccine, efforts to have it ready by the end of the year could be delayed, the Times reported.
In a statement, AstraZeneca described the trial's halt, which was done voluntarily, 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 added that in large trials participants sometimes become sick by chance "but [the cases] must be independently reviewed to check this carefully."
A person familiar with the situation, who spoke on the condition of anonymity, told the Times that the participant who had the suspected adverse reaction had been volunteering in a trial based in the United Kingdom. The volunteer was diagnosed with transverse myelitis, an inflammatory syndrome that affects the spinal cord and is often sparked by viral infections.
"This is the whole point of doing these Phase 2, Phase 3 trials," Dr. Phyllis Tien, an infectious disease physician at the University of California, San Francisco, told the Times. "We need to assess safety, and we won't know the efficacy part until much later. I think halting the trial until the safety board can figure out whether or not this was directly related to the vaccine is a good idea."
The news also came the same day that nine drug companies, including AstraZeneca, made a joint pledge to reaffirm that they would not move forward with any vaccines before thoroughly vetting them for safety and efficacy.
Second wave likely this fall
In a sobering illustration of the toll the coronavirus pandemic took this summer, tallies now show the number of Americans who have died of COVID-19 jumped from just under 100,000 to over 186,000 between Memorial Day and Labor Day, while cases more than quadrupled, to over 6.2 million.
As troubling as those statistics are, public health experts warn the fall and winter could be even worse, the Washington Post reported.
A cold-weather surge of COVID-19 cases could trigger a much-feared "second wave" of infections and deaths that begins well before Election Day in November, though scientists believe the crest of cases would come weeks later, the Post reported
"My feeling is that there is a wave coming, and it's not so much whether it's coming but how big is it going to be," Eili Klein, an epidemiologist at Johns Hopkins University School of Medicine in Baltimore, told the newspaper.
Still, national numbers have been slowly dropping following surges that showed up in the Sun Belt in early summer, the Post reported.
A model produced by the University of Washington's Institute for Health Metrics and Evaluation (IHME) predicts a daily death toll of 1,907 on Election Day, roughly double the current number. Under the IHME forecast, the numbers would continue to rise until early December, peaking at more than 2,800 deaths daily.
By year's end, over 410,000 will have died under the model's most likely scenario. That's more than double current total.
"I firmly believe we will see distinct second waves, including in places that are done with their first waves. New York City, I'm looking at you," Andrew Noymer, an epidemiologist at the University of California at Irvine, told the Post.
"I expect fall waves starting in mid-October and getting worse as fall heads into winter, and reaching a crescendo certainly after the election," he told the newspaper. "Some places will peak around Thanksgiving, some places will peak around Christmas, some places not until January and February."
Top Trump adviser says October vaccine 'extremely unlikely'
As the Trump Administration races to produce a COVID-19 vaccine as quickly as possible, the chief adviser for the White House vaccine program said it was "extremely unlikely, but not impossible" that a vaccine could be available by the end of October.
Speaking with National Public Radio last week, Dr. Moncef Slaoui said that the U.S. Centers for Disease Control and Prevention's guidance to states to prepare for a vaccine as early as late October was "the right thing to do" in case a vaccine was ready by that time.
"It would be irresponsible not to be ready if that was the case," Slaoui said, adding that he first heard about the new CDC guidance from media reports, the Post said.
Still, Slaoui, the chief scientific adviser for Operation Warp Speed, described getting a vaccine by late October as a "very, very low chance."
That message ran counter to optimistic claims from the White House that a vaccine could be ready for distribution before the November presidential election. During the National Republican Convention, President Trump announced that a vaccine could be ready "before the end of the year or maybe even sooner."
Slaoui did confirm that the two main vaccine candidates, referred to as Vaccine A and Vaccine B by the CDC, were being developed by Pfizer and Moderna, respectively. He said there was "no intent" to introduce a vaccine before clinical trials were completed. The trials would only be completed when an independent safety monitoring board affirmed the effectiveness of the vaccine, he added.
While expressing doubt about an October timeline, Slaoui believes "that we will have a vaccine available before the end of the year and it will be available in quantities that can immunize patients, subjects at the highest risk."
By the end of the year, there should be enough doses of the vaccine ready to immunize "probably between 20 and 25 million people."
There should be enough doses to immunize the U.S. population "by the middle of 2021," he added.
Cases keep mounting
By Wednesday, the U.S. coronavirus case count passed 6.3 million as the death toll passed 189,500, according to a New York Times tally.
According to the same tally, the top five states in coronavirus cases as of Wednesday were: California with over 746,000; Texas with more than 670,000; Florida with over 650,000; New York with more than 445,000; and Georgia with over 268,600.
Curbing the spread of the coronavirus in the rest of the world remains challenging.
On Tuesday, India overtook Brazil to become the country with the second-highest number of coronavirus cases in the world, the Post reported. That pushes the country's case count past 4.3 million; only the United States has recorded more. Nearly 74,000 people in India have died of COVID-19, making it the worst-affected nation in Asia, the Post reported.
Meanwhile, Brazil posted nearly 4.2 million cases and over 127,400 deaths as of Wednesday, the Times tally showed.
Unlike the United States and Brazil, where the number of new cases have eased in recent weeks, India has been reporting the highest daily increases in cases in the world since early August, the Post reported.
After instituting the world's largest lockdown this spring, Jayaprakash Muliyil, a leading Indian epidemiologist, predicted that the country's daily reported cases will continue to rise in coming weeks. He told the Post that the daily cases could double over the next month before retreating.
Cases are also spiking in Russia: The country's coronavirus case count has passed 1 million, the Times reported. As of Wednesday, the death toll in Russia was 18,080.
Worldwide, the number of reported infections passed 27.6 million on Wednesday, with over 898,000 deaths, according to the Hopkins tally.
The U.S. Centers for Disease Control and Prevention has more on the new coronavirus.
This article: Copyright © 2020 HealthDay. All rights reserved.