India reports its highest number of Covid-19 cases in 24 hours yet

This illustration, created at the Centers for Disease Control and Prevention (CDC), reveals ultrastructural morphology exhibited by coronaviruses.  Centers for Disease Control and Prevention (CDC)

The director of the US Centers for Disease Control and Prevention (CDC) has called on all Americans to pull together "for your country" to help stop the spread of Covid-19, saying the US was in a "war" against the disease.

“I'm asking you to do four simple things: wear a mask, social distance, wash your hands and be smart about crowds,” CDC Director Dr. Robert Redfield said Wednesday in an interview with WebMD.

Redfield reiterated his warning that if Americans do not adhere to these recommendations, this could be “the worst fall (season), from a public health perspective, we've ever had.”

The CDC director urged Americans to prepare for a difficult fall season by getting the flu vaccine.

Redfield said the CDC has purchased 10 million doses of the flu vaccine for uninsured adults this year, compared to the typical 500,000 doses. 

Phase 3 trials are currently underway for several coronavirus vaccine candidates.  

Redfield said he is cautiously optimistic that the United States will have one or more vaccines deployed by the start of 2021.

Minister of State for AYUSH, Shripad Naik.  Vipin Kumar/Hindustan Times via Getty Images

Indian cabinet minister Shripad Naik tested positive for Covid-19 Wednesday, he announced on his official Twitter page. 

Naik heads the Ministry of Ayurveda, Yoga and Naturopathy, Unani, Siddha and Homoeopathy -- also known as AYUSH. 

Naik is the latest member of Prime Minister Narendra Modi's government to test positive for Covid-19, including Home Minister Amit Shah and Petroleum Minister Dharmendra Pradhan.  

Naik tweeted Wednesday that he was tested even though he was not exhibiting any symptoms. 

Relatives and bystanders, some of them wearing protective suits, line up to get oxygen cylinders for patients outside a hospital in Srinagar, Indian controlled Kashmir, on Wednesday, August 12. Mukhtar Khan/AP

India recorded 66,999 new coronavirus cases in the past 24 hours, the country's health ministry announced Thursday -- its highest confirmed number of daily infections yet. 

The country has reported 2,396,637 Covid-19 cases since the outbreak began, according to the ministry, the third highest in the world after the United States and Brazil.

More than 653,000 cases remain active. The total number of recovered patients in India stands at over 1.6 million, according to the government.

In India, not all patients require a test to be considered recovered. Patients with mild and moderate symptoms are considered no longer active after 10 days of symptom onset if they meet certain conditions, and a test to confirm that they no longer have the virus is not required. However, severe cases can only be discharged after one negative coronavirus test.

The health ministry also announced 942 new coronavirus-related fatalities in the past 24 hours, bringing India's death toll to 47,033.

According to the Indian Council of Medical Research, more than 26.8 million coronavirus samples have been tested so far.

CNN is tracking worldwide coronavirus cases here:

Another 55,910 coronavirus cases were recorded in the United States on Wednesday, bringing the country's total number of confirmed infections to at least 5,197,118, according to Johns Hopkins University's tally.

In addition, Johns Hopkins reported 1,499 new US fatalities from Covid-19. The country's death toll for the epidemic is now at least 166,026.

The totals include cases from all 50 states, the District of Columbia and other US territories, as well as repatriated cases. 

CNN’s map is tracking US coronavirus cases:

A general view of AstraZeneca offices and the corporate logo in Cambridge, England. Alastair Grant/AP Photo

Mexico and Argentina will produce “between 150 and 250 million doses” of a coronavirus vaccine developed by AstraZeneca, Mexico’s Foreign Minister Marcelo Ebrard announced on Twitter on Wednesday.  

Ebrard said financing for the drug's production will be provided by the Carlos Slim Foundation, a Mexico-based nonprofit founded by billionaire Carlos Slim. 

Further details will be announced on Thursday, Ebrard added.

Race to find a vaccine: There are 28 coronavirus vaccines in human trials around the world, according to the World Health Organization.

Six pharmaceutical companies, including AstraZeneca, have reached deals with the US government to develop a Covid-19 vaccine as part of a federal push to curb the pandemic. The US Food and Drug Administration has previously said it would only approve a vaccine if it meets a 50% efficacy requirement.

Russia raised eyebrows on Tuesday when it announced the world's first approved coronavirus vaccine for public use.

Last month, researchers in one of India's largest cities made a surprising discovery. Of the nearly 7,000 blood samples taken from people in Mumbai's slums, 57% tested positive for coronavirus antibodies.

While some were alarmed by the results of the study conducted by the Mumbai authorities and the Tata Institute of Fundamental Research, others were optimistic.

Mumbai's slums, where social distancing is nearly impossible, might now have some of the highest levels of immunity in the world -- only 23.5% of samples taken by India's National Center for Disease Control tested positive for antibodies in Delhi and 14% tested positive in New York, in a study sponsored by the New York State Department of Health.

Scientists believe it's likely that recovering from coronavirus leaves a person with some immunity, but it's not clear how strong it is or how long it lasts. Herd immunity is the idea that a disease will stop spreading once enough of a population becomes immune -- and is appealing because, in theory, it might provide some protection for those who haven't been ill.

If more than half of people in Mumbai's slums had contracted coronavirus, could they be approaching herd immunity -- without a vaccine? 

One expert thought so. 

But others have been more cautious. David Dowdy, an associate professor in epidemiology at Johns Hopkins Bloomberg School of Public Health, said it was possible that the researchers had used a test that created false positives. 

And Om Shrivastav, an infectious diseases expert in Mumbai, cautioned that, less than eight months into the virus' existence in society, it was too early to make any "decisive, conclusive statements." 

Read the full story:

Dr. Ashley Bloomfield speaks during a Covid-19 new briefing on August 13, in Wellington, New Zealand.  Mark Tantrum/Getty Images

New Zealand’s top health official on Thursday said that the genome sequence from the country’s new coronavirus cluster “closely resembles” patterns from the United Kingdom and Australia.

Bloomfield added that the genome sequencing investigations are still ongoing and there is currently “no exact link” between the genome sequence of the new locally transmitted cases and imported cases in managed isolation quarantine facilities.  

New cluster: New Zealand authorities reported 14 new coronavirus cases on Thursday, of which 13 were locally transmitted. 

Three of the new cases were from employees at Americold, the workplace of one of the previously reported cases, and an additional seven cases were family members of employees at the firm. 

Authorities are testing at Americold's warehouse for Covid-19, but New Zealand Prime Minister Jacinda Ardern emphasized that the most likely cause of the outbreak was human to human transmission.

"We are wanting to rule everything out," she said. 

Los Angeles Mayor Eric Garcetti wears a face mask at a news conference at a coronavirus testing site at Lincoln Park, on August 5, in Los Angeles. Kirby Lee via AP

Los Angeles is "making good progress" and has seen success over the past three weeks in response to the coronavirus pandemic, Mayor Eric Garcetti announced in a news conference on Wednesday.

According to Garcetti, there are fewer coronavirus cases, deaths, hospitalizations, a lower positivity rate, and stable and strong hospital bed availability in Los Angeles hospitals. 

The mayor attributed the drop in new infections and deaths to the wearing of face masks, washing hands, maintaining physical distance from others, and staying home, calling these actions “sacrifices to protect one another.”

The rate of transmission for Los Angeles County has dropped to 0.86 from 0.91 last week, Garcetti said.

While the Covid-19 threat level in Los Angeles still remains at “orange” -- the second highest level meaning residents should minimize contact with anyone outside of their households -- Garcetti said the past few weeks have made a difference and there are no plans to move forward with any further closures or restrictions. 

Electronic reporting system issues: Garcetti confirmed that a fraction of the case data numbers from a backlog has been received. He also warned that case numbers may increase once the county receives the backlog of data.

Garcetti urged residents to continue wearing masks, washing hands, physical distancing, and staying home.

“These things work and they are working to drive down the curve.”

Prime Minister Jacinda Ardern speaks during a news conference on August 13, in Wellington, New Zealand. Mark Tantrum/Getty Images

New Zealand health officials said Thursday they had identified 14 new coronavirus cases as the country tackles a fresh outbreak that ended a run of more than 100 days without any locally transmitted infections.

Officials also warned they were likely to find more cases.

Prime Minister Jacinda Ardern reiterated that sentiment.

"As we all learnt from our first experience with Covid, once you identify a cluster it grows before it slows. We should expect that to be the case here," she said

All but one of the cases are locally transmitted, and are connected with four confirmed cases in Auckland, the country's most populous city. The other case is a woman in managed isolation who recently entered the country from the Philippines.

Of the 13 cases that are locally transmitted, three patients are employees at Americold, a cool storage facility where one of the previously reported cases worked. Seven of the cases are family members of Americold employees.  

One school student also tested positive for the virus, Bloomfield said. The student is a close contact of one of the four cases reported on Tuesday. 

What's happening in New Zealand: On the weekend, the country -- which has been held up as an example of how to combat the virus -- marked 100 days without any locally transmitted infections.

But that streak came to an end this week. On Tuesday, New Zealand announced four new locally-transmitted cases -- and on Wednesday, Auckland went into a level 3 lockdown for three days.

Parliament was set to be dissolved Wednesday ahead of the country's national election in September, but it was postponed. Ardern hasn't announced whether she will postpone the election, which is scheduled for September 19.

New Zealand has recorded more than 1,200 confirmed coronavirus cases, including 22 deaths.