A pandemic of the novel coronavirus has now killed more than 961,000 people worldwide.
Over 31.1 million people across the globe have been diagnosed with COVID-19, the disease caused by the new respiratory virus, according to data compiled by the Center for Systems Science and Engineering at Johns Hopkins University. The criteria for diagnosis -- through clinical means or a lab test -- has varied from country-to-country. Still, the actual numbers are believed to be much higher due to testing shortages, many unreported cases and suspicions that some national governments are hiding or downplaying the scope of their outbreaks.
The United States is the worst-affected country, with more than 6.8 million diagnosed cases and at least 199,552 deaths.
California has the most cases of any U.S. state, with more than 786,000 people diagnosed, according to Johns Hopkins data. California is followed by Texas and Florida, with over 713,000 cases and over 683,000 cases, respectively.
Nearly 170 vaccine candidates for COVID-19 are being tracked by the World Health Organization, at least six of which are in crucial phase three trials.
Worldwide cases up by 2 million but deaths down, says WHO
The number of new global COVID-19 cases increased by 2 million in the last week, the highest one-week jump since the pandemic began, according the the World Health Organization.
However fatalities decreased by 10% worldwide over the same time span, the organization reported.
The Americas reported a 22% decrease in deaths, while Europe reported a 27% increase.
Africa is the only region to report declines in both new cases and deaths.
Southeast Asia accounted for 35% of the week's new cases reported and 25% of all deaths, the WHO said.
Coronavirus cases on the rise in 3 states
As of last week, new coronavirus cases in the U.S. have been increasing, according to health data.
On Sept. 13, the seven-day average for new cases in the country jumped by 13%, according to state health data collected by the COVID Tracking Project. Three states saw major increase in new cases, according to the data.
Since Sept. 3, new coronavirus cases in Wisconsin have increased by 156.3%, the data showed. The seven-day average of new coronavirus cases has in Utah surged by 117.6% since Sept. 10, according to the data. The seven-day average of new coronavirus cases in Idaho jumped by 17% since Sept. 14, the data showed.
ABC News' Arielle Mitropoulos contributed to this report.
WHO: Aims to distribute 2 billion vaccine doses by the end of 2021
The nations, which do not include the U.S., China and Russia, represent 64% of the world’s population. WHO leaders said their target is to issue 2 billion vaccine doses through COVAX by the end of 2021, which would vaccinate around 25.6% of the world's 7.8 billion population, under a one-dose regimen.
"There's no guarantee that any vaccine in development will work," WHO Director-General Dr. Tedros Adhanom Ghebreyesus said in Geneva, but he added, "we must move heaven and earth" to ensure equitable access to diagnostics, therapeutics and vaccines.
Higher income governments are committed to provide an upfront payment to reserve doses by Oct. 9, 2020, WHO said.
The allocation of vaccines, once licensed and approved, will be guided by an Allocation Framework released Monday by WHO following the principle of fair and equitable access, ensuring no participating economy will be left behind.
"The race for vaccines is a collaboration not a contest," Tedros said, "It's in every country's best interest, we sink or we swim together."
ABC News' Christine Theodorou contributed to this report.
CDC adds then removes guidance on airborne spread
The U.S. Centers for Disease Control and Prevention issued and later removed updated guidance on its website to address growing evidence of limited airborne transmission of the virus that caused COVID-19.
It’s already known that the novel coronavirus is most commonly transmitted "through respiratory droplets or small particles, such as those in aerosols, produced when an infected person coughs, sneezes, sings, talks, or breathes."
On Friday, the CDC also included that "There is growing evidence that droplets and airborne particles can remain suspended in the air and be breathed in by others, and travel distances beyond 6 feet (for example, during choir practice, in restaurants, or in fitness classes)," noting that "In general, indoor environments without good ventilation increase this risk."
But on Monday morning, the updated information on airborne transmission was removed from the site and in its place, the agency explained that posting the new information was done in error.
"A draft version of proposed changes to these recommendations was posted in error to the agency's official website. CDC is currently updating its recommendations regarding airborne transmission of SARS-CoV-2 (the virus that causes COVID-19). Once this process has been completed, the update language will be posted."
The World Health Organization acknowledged in July that the novel coronavirus could spread through the air, after hundreds of scientists called for the global health arm of the United Nations to recognize the risk of airborne transmission.
ABC News' Eric Strauss and Sony Salzman contributed to this report.