(Bloomberg) -- U.S. regulators are poised to approve a third vaccine dose for people with weak immune systems as a new study showed the benefits of an extra shot in transplant patients. 

Separately, health officials in the nation urged pregnant women to get vaccinated as new evidence showed no increased risk of miscarriage. California became the first U.S. state to require all teachers and school personnel to get vaccinated or undergo weekly testing.

The New York Stock Exchange is instituting a vaccine mandate for everyone entering its trading floors. Moderna Inc. plans to double enrollment in a trial of its Covid vaccine in children under age 12, following a request from U.S. regulators to collect additional safety data.

Shanghai is going back on high alert as China witnesses an outbreak of the delta variant of the coronavirus. Clotting from Covid-19 vaccines is very rare but can be “devastating,” a study found.

Key Developments:

• Global Tracker: Cases top 204.4 million; deaths pass 4.3 million
• Vaccine Tracker: More than 4.51 billion doses administered
• Clotting from Covid shots is rare but can be ‘devastating’
• Understanding the debate over booster shots: QuickTake
• Global travel during Covid-19: Where you can and can’t go
• Restarting cruises has been a game of ‘whack-a-mole’

Puerto Rico’s Vaccine Mandates (5:50 a.m. HK)

Virtually all service-sector workers in Puerto Rico will be required to have a Covid-19 vaccine starting Aug. 23, Governor Pedro Pierluisi said Wednesday.

The rule will apply to in-person employees of restaurants, bars, cafes, movie theaters, convention centers and activity centers. In addition, all establishments that serve prepared food or drinks will be required to ask their clients for proof of vaccination, a recent negative Covid-19 test, or proof that they’ve had Covid in the last three months and recovered. Businesses that do not want to comply with the client-questioning rule will be forced to operate at 50% capacity, Pierluisi said.

The executive order comes as infection rates have hit their highest levels since April, driven by the delta variant. The U.S. territory of 3.3 million has reported more than 130,599 cases of the coronavirus and 2,626 deaths due to Covid-19 since the pandemic began. Last week, the island began requiring visitors to present vaccination cards or negative Covid-19 tests at hotels.

“If these measures do not have a significant impact, I will be forced to implement additional restrictions,” Pierluisi said.

Shanghai Back on High Alert (5:45 a.m HK)

A year after becoming the world’s first major financial center to tame the virus, Shanghai is going back on high alert as the delta variant spreads in China.

Shanghai’s  more than 470,000 finance professionals, who have nearly all been back at work and mask-free since the middle of last year, now face regular temperature scans and checks to enable contact tracing. At some banks, people were told to put their masks back on in common areas and hosting visitors in conference rooms was prohibited again.

Among those shifting their stance is Fidelity International Ltd., which is again discouraging its Shanghai employees from non-essential travel and urging them to avoid large crowds. Some are preparing for the worst. Guotai Junan Securities Co. is drawing up contingency plans including rotating shifts to ensure continuous operations if necessary, according to a memo last week. Departments at the brokerage with vaccination rates below 90% are urged to get their staff inoculated.

FDA Plans to Clear Third Covid Shot for Some (5:40 a.m. HK)

U.S. drug regulators are set to clear a third dose of Covid vaccines for people with weak immune systems as a new study showed the benefits of an extra shot in transplant patients.

A third dose of Moderna’s vaccine significantly raised antibody levels against the coronavirus in transplant patients, according a comparison of an extra shot to a placebo in people with weak immune systems. The Food and Drug Administration is set to amend clearances as soon as Thursday for vaccines from both Moderna and Pfizer Inc. to allow extra doses for people with compromised immune systems, according a person familiar with the matter who spoke on condition of anonymity.

Transplant patients and others with weak immune systems often don’t get adequate responses to their first vaccine course and are at the top of the list for getting potential Covid-19 boosters. An advisory committee to the U.S. Centers for Disease Control and Prevention is set to discuss booster shots for immune compromised people this Friday.

Clotting From Shots Rare But Can Be Devastating (5:35 a.m. HK)

Researchers say they’re making progress in understanding a clotting disorder linked to Covid-19 vaccines that they describe as very rare but potentially “devastating.”

The blood-clotting syndrome affected about 1 in 50,000 people under the age of 50 who received the vaccine developed by AstraZeneca Plc and the University of Oxford, according to a study published in the New England Journal of Medicine. Almost a quarter of those patients who definitely or probably had the condition died.  

The chances of death rose to 73% among those with a very low platelet count and other factors, U.K. researchers found. Cases of the disorder, called immune thrombocytopenia and thrombosis, have declined since age restrictions were introduced in the rollout, scientists said Wednesday.

Researchers hope the findings will help countries that are relying heavily on AstraZeneca’s vaccine to respond to the condition and decide who should receive the shot. The inoculation has been dogged by safety concerns that prompted some regulators to limit its use to older adults. The disorder can affect young, otherwise healthy vaccine recipients.

Oklahoma School District to Defy Mask Ban (4:45 p.m. NY)

In Oklahoma City, the Santa Fe South Schools charter district is defying a state law that bans school mask mandates -- the first district in Oklahoma to do so, the Oklahoman newspaper reported Wednesday.

“If this decision keeps a single member of our community from suffering serious health issues or death, it is worth it a thousand times over,” Superintendent Chris Brewster said in a letter to families.

Oklahoma’s seven-day average of new infections surpassed 2,000, the highest since February, the newspaper said.

NYSE to Require Vaccine on Trading Floors  (4:15 p.m. NY)

The New York Stock Exchange will require Covid-19 vaccines for everyone entering its trading floors, joining the ranks of firms taking a more cautious approach amid a new wave of coronavirus cases.

The mandate is set to take effect Sept. 13, Chief Operating Officer Michael Blaugrund said Wednesday in a memo seen by Bloomberg. The policy covers anyone with access to the NYSE and American Options trading floors, including member firms, employees and vendors.

Some people may be granted an exception to the mandate for medical or religious reasons, according to the memo. Those who gain an exemption will have to present a negative test within 48 hours before entry, equivalent to three times a week. They’ll also have to be masked when on the floor, while masks for vaccinated employees remain optional, the memo shows.

McDonald’s Mandates Shots for Office Workers (3:30 p.m. NY)

McDonald’s Corp. said it decided to transition from “strongly encouraging vaccinations” to “requiring vaccinations” for all U.S.-based office workers, according to an internal note obtained by Bloomberg. All U.S.-based employees should get fully vaccinated as soon as possible, by Sept. 27 the latest, it said. The company also pushed back the official office reopening date to Oct. 11 from Sept. 7

California Issues Shot Mandate for Teachers (2:40 p.m. NY)

All California teachers and public school employees must be vaccinated against Covid-19 or submit to regular testing, Governor Gavin Newsom said Wednesday.

The decision came after the San Francisco, Long Beach and Oakland school districts set similar mandates. The rule makes California the first state in the nation to mandate vaccines for all school employees, including bus drivers, janitors and cafeteria workers.

Moderna Doubles Trial Size in Young Children (1:35 p.m. NY)

Moderna Inc. plans to double enrollment in a trial of its Covid vaccine in children under age 12, following a request from U.S. regulators to collect additional safety data.

Moderna’s study will enroll an estimated 13,275 participants ages 6 months to 12 years old, according to a listing on the clinicaltrials.gov website. In a post from late July, the Cambridge, Massachusetts-based company said it would seek to enroll about 7,000.

U.S. Urges Shots for Pregnant Women (1:30 p.m. NY)

U.S. health officials stepped up calls for pregnant women to get vaccinated against Covid-19 as new evidence showed no increased risk of miscarriage from the shots.

Women who received messenger RNA Covid vaccines before 20 weeks of pregnancy have no increased risk of miscarriage or other safety concerns, according to an analysis of an agency registry. The Centers for Disease Control and Prevention updated its message to recommend shots for pregnant women; it had previously said they were eligible.

Lisbon Web Summit to Meet in Person (1:25 p.m. NY)

The Web Summit, which describes itself as the biggest gathering of startups on the globe, will be held in person in Lisbon in November after the event was held online last year due to the coronavirus pandemic.

Web Summit Chief Executive Officer Paddy Cosgrave said on Twitter on Wednesday the event has been given the “full green light.” The announcement takes place as the Portuguese government began easing Covid-19 restrictions as the latest surge of coronavirus infections in the country shows signs of slowing.

Hundreds of speakers and startups are expected to attend the Summit, which will take place from Nov. 1-4.

DeSantis Digs In on Mask-Mandate Ban (11:20 a.m. NY)

Florida Governor Ron DeSantis doubled down on his decision to ban school districts from instituting mask mandates as students begin classes across the Sunshine State.

“Our view is of course this is a decision for the parent to make, just given the uncertainty about what it means particularity for a lot of the young kids to be in that,” he said in a press conference on Wednesday in Pinellas County, surrounded by local teachers and school leaders. “We believe the parent rather than the government should ultimately be able to make that decision.”

Late last month, DeSantis issued an executive order that threatened to withhold state funding from school districts that required students to wear masks. Some districts rebuked the governor and are insisting a face-covering mandate as virus cases continue to swell. Carlee Simon, superintendent of Alachua County Public Schools, said that her district will continue to mandate masks in order to best protect the community, she wrote in a Washington Post editorial on Monday.

DeSantis said that should the Biden administration institute a nationwide mask mandate for students “that is something we would fight back ferociously against.” On Tuesday, Biden said he doesn’t think he has the power to overrule governors on the subject but his administration is “checking on that.”

WHO to Assess More Vaccine Candidates (10:19 a.m. NY)

While Russia’s Sputnik vaccine is still undergoing assessment by the World Health Organization, India’s Bharat shot may have a final evaluation in September, Mariangela Simao, assistant director-general for drug access, vaccines and pharmaceuticals, said Wednesday.

Five other vaccine candidates are beginning assessment in August, including the Novavax shot manufactured by the Serum Institute of India and the Sinopharm vaccine being made in Wuhan, China.

The more vaccines get the WHO’s green light, the more can be shipped via the Covax facility, which aims to distribute Covid inoculations equitably around the world. At the current trajectory, the world could pass 300 million reported cases early next year, according to Director-General Tedros Adhanom Ghebreyesus.

The WHO has already approved several vaccines, including those made by Pfizer Inc., Moderna Inc., AstraZeneca Plc and Johnson & Johnson.

Switzerland May End Free Testing (9:40 a.m. NY)

Switzerland may stop offering free Covid tests for the public starting Oct. 1, as the government struggles to boost the vaccination rate. With just half the population fully inoculated and people returning from summer holidays, the case load has been rising.

The government decided against further loosening restrictions, such as the requirement for masks in public areas. It said it would make a final decision on the Covid tests on Aug. 25. Currently, tests are available at pharmacies and testing sites free of charge, and are required for entry to nightclubs and other large events.

Japan Mulls Wider State of Emergency: Sankei (9:25 a.m. NY)

The Japanese government is considering widening its state of emergency to additional areas and keeping it in force through September, rather than the end of this month, the Sankei newspaper reported, without attribution. It plans to decide on the expansion as soon as next week.

Macron Defends Handling of Crisis (9:16 a.m. NY)

French President Emmanuel Macron rebuffed accusations that he’s handling the Covid-19 crisis in an authoritarian way and renewed his call for people to get vaccinated.

“Never before in our history was a crisis of such magnitude fought in such a democratic way,” Macron said at the beginning of a virtual defense cabinet meeting broadcast on French TV. The president blasted opponents, without naming them, for exploiting the pandemic “to win political market share.”

Macron’s comments followed a fourth consecutive weekend of demonstrations in major French cities against new measures that make access to restaurants, museums and virtually all activities conditional on proof of vaccination or a recent negative test.

Lesotho Prime Minister Tests Positive (9 a.m. NY)

Lesotho Prime Minister Moeketsi Majoro tested positive for Covid-19 before a private trip he had planned. He’s isolating at home and not showing any symptoms, spokesman Buta Moseme said in a statement Wednesday. The landlocked southern African country of 2.1 million people has reported 13,845 cases and 391 deaths.

U.K. School Safety Measures Cut Infections (8:45 a.m. NY)

Less than 1% of U.K. school students and staff tested positive for Covid-19 in June, significantly lower than last autumn, a study released by the Office for National Statistics found. Infection rates were lower in children in schools than among those in the wider population.

The findings give credibility to the government’s plan to put students into “bubbles” and ask those with symptoms to stay home. That may bolster the effort of ministers to convince parents to send children back to school when the academic year begins next month.

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