Coronavirus latest: 'Largest mass fatality incident' in New York City: Report

New York City counted nearly 24,000 confirmed or probable deaths from COVID-19.

A pandemic of the novel coronavirus has now killed more than 948,000 people worldwide.

Over 30.3 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 6.7 million diagnosed cases and at least 198,306 deaths.

California has the most cases of any U.S. state, with more than 776,000 people diagnosed, according to Johns Hopkins data. California is followed by Texas and Florida, with over 701,000 cases and over 677,000 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.

CDC makes major reversal on testing guidelines

The Centers for Disease Control and Prevention on Friday walked back its guidance on who should be tested for COVID-19, saying that asymptomatic people who have come in contact with an infected person should get tested and quarantine for two weeks -- a major reversal from the guidance released last month that said testing might not be necessary for people without symptoms.

The earlier guidance had said that if you came in contact with someone infected, "you do not necessarily need a test" if you don't exhibit any symptoms, but that local public health officials or health care providers might still recommend one.

In an about-face, the CDC said Friday that if someone has been in close contact with a person with COVID-19 infection "you need a test" and to self-isolate for 14 days, even if the test is negative.

Doctors are applauding the new CDC guidance.

Dr. Thomas M. File, Jr., president of the Infectious Diseases Society of America, said in a statement, "The return to a science-based approach to testing guidance from the Centers for Disease Control and Prevention is good news for public health and for our united fight against this pandemic. We urge officials to support the work of controlling this pandemic by following medical guidance of experts in the field.”

ABC News' Stephanie Ebbs and Anne Flaherty contributed to this report.

Southern, northern US borders to stay closed to nonessential travel through Oct. 21

The southern and northern U.S. borders will remain closed to nonessential travel until at least Oct. 21 as part of efforts to stop the spread of coronavirus, Acting Homeland Security Secretary Chad Wolf said Friday.

Wait times at the international checkpoints grew in recent weeks, including for U.S. citizens. Border authorities have closed lanes, added more inspections and are continuing to directly tell travelers about the nonessential restrictions.

ABC News' Quinn Owen contributed to this report.

Israel goes on its 2nd lockdown as Jewish High Holidays begin

Israel's second COVID-19 lockdown started on Friday as the Jewish High Holidays began.

The lockdown, which will last for three weeks, went into effect at 2 p.m. local time. Rosh Hashanah, the Jewish new year, begins Friday night, and is typically a time for family gatherings.

Supermarkets and pharmacies will stay open during the lockdown but schools and nonessential businesses will close.

Synagogues can stay open but there are strict rules as to how many worshippers can go inside at one time. Ten days after Rosh Hashanah is Yom Kippur; attending synagogue is an important part of both holidays.

Israel has over 179,000 people diagnosed with COVID-19. At least 1,196 people have died, according to Johns Hopkins data.

Israel's first nationwide pandemic lockdown ended in May.

New Zealand reports no new cases for 1st time in over a month

New Zealand has reported no new confirmed cases of COVID-19 for the first time since Aug. 10, after a fresh outbreak was discovered in the country's most populous city.

New Zealand's Ministry of Health said Friday that there were no positive results among the 7,360 people tested for COVID-19 the previous day. It's the fourth straight day without any cases of community transmission in the nation of 5 million people, with all recent cases being detected among quarantined travelers returning from abroad.

A cluster of cases emerged in the city of Auckland last month, ending New Zealand's 102-day streak without any local transmission of the novel coronavirus. The outbreak prompted the government to impose a temporary lockdown in the region and reschedule national elections.

Since the start of the coronavirus pandemic, New Zealand's Ministry of Health has identified 1,809 confirmed and probable COVID-19 cases as well as 25 coronavirus-related deaths. There are currently 70 active cases and four coronavirus-related hospitalizations in the country.