The agency’s commissioner asked an external foundation to examine its operations in the wake of the baby formula and vaping crises.The Food and Drug Administration has commissioned a review of its food and tobacco programs following public outrage over baby formula shortages and concerns about flavored nicotine products.Dr. Robert Califf, the head of the F.D.A., said the agency had confronted issues that “have tested our regulatory frameworks and stressed the agency’s operations,” prompting the review announced on Tuesday.The review will be conducted by the Reagan-Udall Foundation, a nonprofit affiliated with the agency. Its directors include nonprofit, academic, corporate and trade association leaders.Congressional lawmakers have hammered the agency for its handling of the infant formula shortage, saying it was slow to heed a whistle-blower’s warning about the troubled plant and did not place a priority on food safety. For several years now, the agency has also been under scrutiny for what some have viewed as an inability to curb the teenage vaping crisis.At a congressional hearing on Wednesday, Dr. Califf defended the agency but said there was still room to examine the structure, funding and leadership of its food safety division that had oversight authority of consumer goods like infant formula.“We have the safest food in the world,” Dr. Califf told members of the Senate Appropriations subcommittee. “Every expert I’ve talked with — the C.D.C. monitors this carefully — said that our food is as safe as it’s ever been. So to say it’s not working is, in my view, just incorrect. That doesn’t mean it can’t be a lot better and that there aren’t major problems. So, you know, that’s why we’re doing this top-down review and plan to make significant changes.”Dr. Califf said that the country’s food system was being challenged by supply chain problems and climate change and that it could better embrace the revolution in technology.The agency is also seeking an examination of its tobacco division and enforcement operations as it faces “an increasing number of novel products that could potentially have significant consequences for public health,” according to an statement. They included highly potent cannabis products, including vapes, that are being tied to addiction and psychosis in teens.Lawmakers and the public have been pressuring the F.D.A. to take action against makers of flavored synthetic nicotine e-cigarettes in flavors that appeal to young people. Congress gave the agency the authority to remove such products from the market in April, and enforcement powers kicked in earlier this month.Yet, the agency has said it was reviewing the marketing applications of about one million applicants submitted by about 200 companies. It issued warnings to two companies, which were selling about 10,000 types of vape products without authorization.Lawmakers and a group of physicians have urged the agency to act faster, though, with a group of Massachusetts General Hospital pediatricians and others calling for “swift action” as more teenagers become addicted to high-nicotine e-cigarettes.The F.D.A. was caught off guard by baby formula shortages spurred earlier this year after it shut down a baby formula factory over quality and safety concerns. The agency had discovered a deadly bacteria called cronobacter sakazakii inside the plant, as reports began to emerge of infant deaths possibly tied to the bacteria.Although the deaths were not definitively linked to the bacteria at the plant, the F.D.A. and the Justice Department entered into a consent decree with the manufacturer, Abbott Nutrition, to oversee process improvements at its Michigan formula plant.Dr. Califf acknowledged that the F.D.A. had limited infant formula supply chain insight during Congressional hearings over the matter. The shortages frightened parents of young children and led to hospitalization of some children who were dependent on formula. Since then, the agency has allowed some foreign formula imports and announced changes to help overseas manufacturers gain access to the U.S. market.Dr. Califf has promised a thorough review of the steps that led to the formula shortage.The external review by the Reagan-Udall Foundation is expected to take two months.

Agency inspectors found a leaking roof, standing water and cracked production equipment before a facility shutdown that led to major shortages.The Abbott Nutrition plant in Michigan that was shut down in February, sparking a widespread baby formula shortage crisis, had a leaking roof, water pooled on the floor and cracks in key production equipment that allowed bacteria to get in and persist, Dr. Robert Califf, the head of the Food and Drug Administration, told a House panel on Wednesday.He detailed “egregiously unsanitary” conditions in the Sturgis, Mich., plant to lawmakers during a hearing, but he also acknowledged that his agency’s response was too slow in addressing problems at the plant.“Frankly, the inspection results were shocking,” Dr. Califf told members of the House Energy and Commerce Subcommittee on Oversight and Investigations. “We had no confidence in integrity of the quality program at the facility,” noting the agency worked with Justice Department officials to dictate steps the company needed to take to turn the facility around.That effort is expected to result in the plant reopening on June 4, Jonathon Hamilton, an Abbott spokesman, said, with some formula expected to begin rolling out June 20. Officials hope new shipments will reach store shelves within six to eight weeks, although resumption of full production at the plant will take longer.Abbott has replaced the leaking roof at the plant as well as the floor, Dr. Califf said.House panel members sharply questioned the commissioner and other agency officials at the hearing. They also demanded answers from an Abbott executive about the plant’s troubled history as well as to how the company would correct glaring deficiencies and ease shortages that have agonized families across the country.Christopher Calamari, an Abbott Nutrition senior vice president, offered little explanation for conditions at the Michigan factory but said he was “deeply, deeply sorry” about the shortages. He said the company was coordinating 50 flights a week from its formula plant in Ireland to a dozen U.S. airports to increase supplies.“We are committed to ensuring that this never happens again,” Mr. Calamari said.Representative Gary Palmer, a Republican of Alabama, pressed Mr. Calamari for specifics about why the company did not fix problems at the plant before the F.D.A. forced its hand.“We prioritize safety and compliance in our plants,” Mr. Calamari said. “And we’re committed to doing so and getting better coming out of this event.”Mr. Palmer replied that he was not satisfied with that response.Committee members pushed back against F.D.A. and Biden administration assertions that it was difficult to recognize in real time the extent of the contamination and the resulting nationwide breakdown in the supply chain. The Abbott plant had produced one-fourth of the nation’s infant formula, including tailored formulas for people with specialized nutritional needs.“There was a life-and-death crisis in front of the F.D.A., but they failed to see the severity of the situations,” said Representative Cathy McMorris Rodgers, a Republican of Washington. “We must solve the immediate issue and also ensure that we are taking action so this situation never happens again.”Read More on the Baby Formula ShortageUnderstand the Shortage: With just a handful of companies making infant formula for the U.S. market, the shutdown of an Abbott Laboratories plant had an outsize effect.Missing Safeguards: The shortage has revealed regulation gaps that make it hard to monitor the deadly bacterium that led to a recall.A Desperate Search: As the United States faces a baby formula shortage, some parents are rationing supplies, or driving for hours in search of them.An Emotional Toll: The shortage is forcing many new mothers to push themselves harder to breastfeed, with some even looking for ways to start again after having stopped.The agency had discovered a battery of problems at the plant last fall. At the same time, reports began emerging of babies who had been hospitalized with a rare bacteria. Cronobacter sakazakii, which can be deadly to infants, was found in four babies who had consumed formula from the plant, according to the Centers for Disease Control and Prevention.Testimony during the hearing made it clear that the F.D.A. took months to try to match the bacteria that sickened the first baby to bacteria that was later found throughout the plant.Dr. Califf testified to the House Oversight Committee about the Abbott Nutrition plant virtually on Wednesday.Brendan Smialowski/Agence France-Presse — Getty ImagesCronobacter strains related to two of the babies did not match samples of the bacteria later found at the plant, although Dr. Califf said the agency considered those results “inconclusive” given shortcomings with genome sequencing.The illnesses set the recall in motion this year. The plant shutdown began Feb. 17 and exacerbated shortages that had been intermittent during the height of the pandemic. Empty shelves have left parents struggling, driving hundreds of miles to find baby formula and, at times, improvising to feed hungry infants.Dr. Califf also acknowledged several ways that the F.D.A. had erred in addressing this problem: Its follow-up inspection in January should have started sooner, he said, adding that the agency took too long to circulate a whistleblower report that arrived in October but did not reach top officials until February.“It was too slow, and there were decisions that were suboptimal along the way,” Dr. Califf said.He told lawmakers that the agency did not receive an immediate notice when a formula plant found the deadly Cronobacter bacteria. Nor does the agency have access to the supply chain information that each of the three main U.S. baby formula manufacturers have in-house.The report of an anonymous whistleblower who said he worked in the Sturgis plant came up repeatedly during the hearing. The whistleblower alleged that safety staff there “celebrated” the F.D.A. overlooking problems after a 2019 inspection and did not destroy enough product when it found Cronobacter in finished products. That top agency officials did not see those claims until February “is stunning to me,” Mr. Palmer said.Details in the report suggested there was “corruption” at the plant, Representative Kim Schrier, Democrat of Washington, charged. Dr. Califf said he could neither confirm nor deny whether there might be criminal proceedings in the future.Mr. Calamari emphasized that the whistleblower’s claims had not been proven. “That’s an open investigation,” he said. “And it’s ongoing.”The report’s allegations resonated with panel members of both parties, including Representative Larry Bucshon, Republican of Indiana, who described himself as a “private-sector guy.”“It seems like that facility’s culture is a problem,” Mr. Bucshon said. “It seems to me that the company needs to do better with oversight.”Mr. Calamari contended that Abbott had invested tens of millions of dollars toward quality and maintenance, and he praised the dedication of employees at the 700,000-square-foot facility, which he visited last week.“I saw the team members there,” he said. “They are empowered to speak up and they are passionate about what they make and they make those products as it was for their own family.”Several panel members called for stricter agency oversight of food safety and more frequent inspections of troubled plants.Navigating the Baby Formula Shortage in the U.S.Card 1 of 6A growing problem.

The company said if the agency approved reopening the plant, production could resume and store shelves would be restocked within several weeks.The Food and Drug Administration on Monday reached an agreement with Abbott Laboratories on the steps needed to reopen the company’s shuttered baby formula plant, which could begin to ease the shortage of infant formula that has frightened and exasperated parents nationwide.The F.D.A. must still grant approval, once the company has taken the steps, for production to resume at the plant in Sturgis, Mich. It has been shut down since February after several babies who had consumed formula that had been produced there fell ill and two died.Abbott described the agreement with the F.D.A. as a “consent decree” and said it would require federal court approval. Once the agency permits the plant to reopen, the company said production could begin within about two weeks and could translate to more formula on shelves in six to eight weeks. The company said it will continue flying formula in from a plant in Ireland.It was unclear how soon the F.D.A. might approve the plant reopening.Abbott’s plant has been offline since February, when the F.D.A. discovered a deadly bacteria, called cronobacter, while swabbing in and near production lines. Abbott disputed that characterization, saying the bacteria were found in “high care” areas that indicate proximity to open products, but not necessarily in or on the production lines themselves.The same type of bacteria has been linked to four recent infant illnesses and two deaths in Minnesota, Texas and Ohio. Abbott said “there is no conclusive evidence to link Abbott’s formulas to these infant illnesses.”The plant shutdown exacerbated an existing supply crisis, as parents rushed to stock up on formula. With store shelves bare in some communities, some have been so desperate they have fed their infants powdered oatmeal cereal and fruit juice, even though pediatricians say formula or breast milk is a crucial source of nutrition from birth to the first birthday.In addition to the F.D.A.’s actions, Representative Rosa DeLauro, a Democrat from Connecticut, said in an interview on Monday that she planned to introduce a bill that would ease the process of importing infant formula from F.D.A.-regulated foreign plants. She also said she plans to hold hearings in the House to review what went wrong in the run-up to the discovery of the bacteria and shortages.“Both the company and the F.D.A. have got to be held accountable in order to move forward,” Ms. DeLauro said. She said she had called for investigation by the Health and Human Services inspector general, and invited Abbott to testify at a hearing set for May 25.Problems at the Abbott Sturgis plant surfaced in September during the F.D.A.’s first routine inspection there since the Covid-19 pandemic began. Inspectors discovered standing water inside the plant and personnel working directly with formula without proper hand hygiene, according to agency documents.The following month, a whistleblower who worked at the plant filed a complaint under the Food Safety Modernization Act claiming that plant leaders celebrated concealing information from the F.D.A. and omitted key information from official documents.The F.D.A. returned to the plant on Jan. 31 and discovered persistent problems, including the presence of cronobacter bacteria near production lines, according to agency records.The F.D.A. and Abbott shut down manufacturing and issued a wide-ranging recall of Abbott’s infant formula on Feb. 17. Since then, supplies have dwindled in stores, setting parents on frantic trips to find formula to feed their babies, some of whom reject a new or unfamiliar taste.On Monday morning, the F.D.A. commissioner, Dr. Robert. M Califf, said on CNN that the agency was working on the supply chain to get the needed formula back on store shelves.Navigating the Baby Formula Shortage in the U.S.Card 1 of 6A growing problem.

The move follows recalls of other medications found to have higher levels of potential carcinogens.Pfizer is recalling some shipments of its blood pressure drug Accuretic, as well as authorized generic versions of the medication, saying that a cancer-causing compound in those lots exceeded the acceptable daily intake level.The compound in the medication is nitrosamine, which is also found in water and beer as well as some foods including bacon and grilled meats. It is believed to pose a small risk of cancer in patients taking the drugs for an extended time.Such recalls have become common in recent years as private labs and companies have detected cancer-causing impurities and set off wide recalls, especially in blood pressure drugs. In September 2020, the Food and Drug Administration urged companies to look for these compounds on a regular basis. The agency announced another nitrosamine-related recall on Wednesday for a Sandoz drug meant to reduce discomfort related to painful musculoskeletal conditions.In 2018, the F.D.A. announced a recall of medications that contain valsartan after NDMA, a probable carcinogen, was discovered in them.A wave of recalls ensued after Valisure, then a pharmacy company that regularly tests medications for impurities, indicated the presence of nitrosamine in ranitidine, an ingredient in the heartburn drug Zantac. Valisure petitioned the F.D.A. to broaden testing after ranitidine was found to have a type of nitrosamine called N-nitrosodimethylamine, or NDMA, which is considered a probable carcinogen.Drugs such as metformin, for people with diabetes, and Chantix, for those trying to quit smoking, have also faced recalls related to probable carcinogens.Accuretic has relatively few users: About 1,300 people took it in 2020. Its generic formulation has more, about 192,000 users, according to data from IQVIA, an analytics company. The generic drug comprises the ingredients quinapril and hydrochlorothiazide and generated about $4.7 million in sales in 2020, IQVIA data show.Accuretic is used to treat hypertension, or high blood pressure.Food and Drug AdministrationPfizer said in a news release that it was not aware of any adverse events related to the Accuretic recall. It said the benefits of taking the drug outweighed the risks, adding that the drug lowered blood pressure and reduced the risk of strokes and heart attacks. The company advised patients to talk to their doctors about alternative treatment options.On Wednesday, David Light, a founder of Valisure, said: “We’re now over three years after the initial discoveries of nitrosamine impurities in major medications and continuing to see the ripple effects grow.”He also noted that his team had discovered benzene, a known carcinogen, in consumer products including sunscreen and body sprays and that the F.D.A. even more quickly began asking industry to broaden its own benzene testing.

Dr. Anthony S. Fauci, the Biden administration’s top adviser on the pandemic, predicted on Sunday an “uptick” in coronavirus infections similar to the current increase in Europe, despite the current decline in cases, hospitalizations and deaths in the United States.It is “no time at all to declare victory, because this virus has fooled us before and we really must be prepared for the possibility that we might get another variant,” Dr. Fauci said on ABC’s “This Week.” “And we don’t want to be caught flat-footed on that.”While anticipating a new rise, Dr. Fauci said that at this time he does not expect a surge. Still, the BA.2 subvariant has been shown to be a more contagious version of the Omicron variant, though it, too, causes less-severe illness in most people.Epidemiologists have said the current lull in U.S. cases mirrors the dip that Europe enjoyed before many officials in the region relaxed restrictions like indoor masking.Global coronavirus cases by regionThis chart shows how reported cases per capita have changed in different parts of the world.

A split committee vote revealed concerns about the opioid epidemic and abortion policies, foreshadowing a likely close vote on confirmation by the full Senate.A divided Senate committee on Thursday advanced the nomination of Dr. Robert Califf to become commissioner of the Food and Drug Administration to the full Senate, with some Democrats citing concerns over the nominee’s commitment to combating the opioid epidemic.The committee’s vote of 13 to 8 suggests that the full Senate vote will be close. A date for the Senate’s vote on confirmation has not been set.Four Republican members of the Senate Committee on Health, Education, Labor and Pensions, including Senator Richard Burr of North Carolina, voted in favor of Dr. Califf’s nomination. Senator Burr, the ranking Republican member, noted that the commissioner’s role was one of the “most significant public health positions in the federal government” and that the agency had been without a Senate-confirmed leader for nearly a year. He urged other Republicans to support Dr. Califf, citing his “unparalleled experience” and willingness to support innovation in the medical field. G.O.P. committee members who voted against him mostly cited concerns about abortion policies.Senator Bernie Sanders, independent of Vermont, and Senators Maggie Hassan of New Hampshire and Edward Markey of Massachusetts, both Democrats, indicated they planned to vote against confirming Dr. Califf for the post. They are all from New England states hard-hit by opioids, though Senator Sanders also criticized Dr. Califf’s journey through the “revolving door” from the F.D.A. to private industry.Senator Joe Manchin, Democrat of West Virginia, a state which was particularly devastated by overdose deaths, had condemned Dr. Califf’s track record on opioids and said he would vote against confirmation. If confirmed, Dr. Califf would lead an agency that had been under intense scrutinyduring the pandemic, as it weighed the safety of coronavirus vaccines and treatments, and reviewed dozens of masks and tests.Most recently, the agency has been criticized for what some consider the sluggish approval of rapid at-home tests, which has led to shortages as the Omicron variant has caused a spike in infections, and as demand has soared for tests for schoolchildren and workers. The agency said that it had concerns about the tests’ sensitivity but not the overall accuracy.High-risk patients who test positive for Covid-19 are also facing severe shortages of medications that are effective against the variant — even as the agency remains the gatekeeper to therapies and diagnostics that could help.On Dec. 14, Dr. Califf appeared before the Senate committee, answering questions about the pandemic, the opioid crisis and other topics.As a cardiologist, Dr. Califf spent decades leading clinical trials at the Duke University Medical Center in North Carolina. Most recently, he led clinical policy and strategy for Verily, the life sciences arm at Alphabet, the parent company of Google. During the hearing, he emphasized the value of existing data, much in patients’ electronic medical records, to help answer difficult questions about the evidence for drugs and devices.Republicans asked how he would handle rules around medications to induce abortion, which had been relaxed during the pandemic after years of tight restrictions. Two days after the hearing, the F.D.A. — under Dr. Janet Woodcock, the interim commissioner — announced that it would permanently lift restrictions, allowing patients to terminate a pregnancy in the first 10 weeks after a telemedicine visit with medications taken at home.Senator Tommy Tuberville, a Republican committee member from Alabama, said in a statement that the recent decision informed his committee vote. “I believe Dr. Califf will continue to advance this administration’s pro-abortion agenda, and I cannot support his nomination,” he said.Senator Mike Braun, a Republican from Indiana, also said he opposed the nomination over abortion policies and opioid concerns. “Under his leadership in 2016, the F.D.A. expanded access to the dangerous chemical abortion drug mifepristone and failed to take action to stem the tide of the opioid crisis ravaging our country,” he said in a statement.Dr. Califf was previously confirmed in a 89-to-4 Senate vote to lead the F.D.A. during the last year of the Obama administration. If confirmed again, he will face key decisions on tobacco control as he tries to balance e-cigarettes as a tool to help some quit smoking without creating a new generation of users. Scrutiny around accelerated approvals of drugs will be heightened, given the current debate over the agency’s approval of the controversial Alzheimer’s drug Aduhelm.After Senator Sanders denounced Dr. Califf’s ties to pharmaceutical firms, which include consulting fees and stock ownership amounting to as much as $8 million, the nominee told the Senate panel in mid-December that he would comply with ethics rules set by the F.D.A. and its parent agency, the Department of Health and Human Services.Senator Hassan of New Hampshire also voted against Dr. Califf’s nomination. She had pressed him in December on the F.D.A.’s failure to update the labeling of opioid medications. Dr. Califf said the agency would continue to review the evidence coming in.“The evidence has been here for a long time,” she responded. “It’s the evidence of thousands of people, hundreds of thousands of people, dying in this country.”Senator Markey of Massachusetts, who is not on the committee that voted on Thursday, also issued a statement citing opioid policy failures and saying he would vote against Dr. Califf. The F.D.A. “repeatedly rubber-stamped new prescription opioids,” and “acted too slowly to remove them from the market or place restrictions on their labels,” he said.Senator Markey said he was dissatisfied after meeting with Dr. Califf late last year, noting that he “did not commit to the decisive and comprehensive action necessary” to regulate opioids.

Most U.S. doctors have no way to determine which variant of the coronavirus a patient is carrying, a distinction that could mean the difference between life and death.High-risk patients carrying the Delta variant could benefit greatly from two particular monoclonal antibody treatments shown to reduce hospitalization and death. But those medications would most likely do nothing for patients with Omicron, who would only respond to a third antibody treatment that is in very short supply.While U.S. officials have endorsed using a workaround test that can identify Omicron’s genetic signature, experts say it’s not feasible for large health systems facing a crush of patients to employ in each case.That makes treating patients challenging in places like Maryland, where cases are spiking and Omicron accounts for roughly 58 percent of them. The Delta variant is also holding strong in the Great Plains and swaths of the West, including California.While there is no approved test to determine each individual’s variant, a national network of state and other labs use genome-sequencing tests to track variants broadly in communities. Health systems then use those regional estimates or their own data to decide which antibody treatments to use in their clinics and hospitals.Many of them concluded that a community of largely Delta patients would benefit most from the antibody drugs made by Regeneron and Eli Lilly, while communities where Omicron patients are predominant would benefit from antibodies from GlaxoSmithKline and Vir Biotechnology.Preparing Covid-positive samples for genomic sequencing at the Washington State Department of Health in Shoreline, Wash.Ted S. Warren/Associated PressFederal officials have dabbled with making the decision for the nation. On Dec. 23, they stopped shipments of antibody treatments by Eli Lilly and Regeneron after the Centers for Disease Control and Prevention said 73 percent of U.S. Covid cases were Omicron.An outcry followed from Republican political leaders, who argued that some people in their states were still infected with Delta. And on Tuesday, the C.D.C. slashed its estimate of national Omicron cases to 59 percent. On Dec. 31, federal officials resumed national shipping all of the antibody treatments.For the next few weeks, as the country grapples with this uneven mix of both variants, tailoring treatments to each patient will be “extraordinarily difficult,” said Dr. Alex Greninger, assistant director of the clinical virology laboratories at the University of Washington Medical Center.Dr. Greninger is credited with developing one of the first tests to detect the coronavirus in the United States. But he is pessimistic that health systems can pivot quickly to sort out which patients have Delta or Omicron. And although a shortcut test can detect Omicron, there’s no simple way to report the results in bulk, he said.What’s more, the genome sequencing used by public health officials takes nearly a week — too long to target the early antibody treatments that have been found to reduce the need for hospitalizations. That makes patient care particularly difficult right now, said Dr. Mark Siedner, an infectious disease clinician and researcher at Massachusetts General Hospital.In Massachusetts and nearby states, an estimated 44.5 percent of cases are Omicron. Dr. Siedner said his health system has stopped using the Regeneron and Eli Lilly antibodies that are not effective against Omicron and are “anxiously awaiting” more doses of the effective treatment by GlaxoSmithKline and Vir Biotechnology.“We’re in a holding pattern and it’s a terrible time to be in that place,” he said.

Most U.S. doctors have no way to determine which variant of the coronavirus a patient is carrying, a distinction that could mean the difference between life and death.High-risk patients carrying the Delta variant could benefit greatly from two particular monoclonal antibody treatments shown to reduce hospitalization and death. But those medications would most likely do nothing for patients with Omicron, who would only respond to a third antibody treatment that is in very short supply.While U.S. officials have endorsed using a workaround test that can identify Omicron’s genetic signature, experts say it’s not feasible for large health systems facing a crush of patients to employ in each case.That makes treating patients challenging in places like Maryland, where cases are spiking and Omicron accounts for roughly 58 percent of them. The Delta variant is also holding strong in the Great Plains and swaths of the West, including California.While there is no approved test to determine each individual’s variant, a national network of state and other labs use genome-sequencing tests to track variants broadly in communities. Health systems then use those regional estimates or their own data to decide which antibody treatments to use in their clinics and hospitals.Many of them concluded that a community of largely Delta patients would benefit most from the antibody drugs made by Regeneron and Eli Lilly, while communities where Omicron patients are predominant would benefit from antibodies from GlaxoSmithKline and Vir Biotechnology.Preparing Covid-positive samples for genomic sequencing at the Washington State Department of Health in Shoreline, Wash.Ted S. Warren/Associated PressFederal officials have dabbled with making the decision for the nation. On Dec. 23, they stopped shipments of antibody treatments by Eli Lilly and Regeneron after the Centers for Disease Control and Prevention said 73 percent of U.S. Covid cases were Omicron.An outcry followed from Republican political leaders, who argued that some people in their states were still infected with Delta. And on Tuesday, the C.D.C. slashed its estimate of national Omicron cases to 59 percent. On Dec. 31, federal officials resumed national shipping all of the antibody treatments.For the next few weeks, as the country grapples with this uneven mix of both variants, tailoring treatments to each patient will be “extraordinarily difficult,” said Dr. Alex Greninger, assistant director of the clinical virology laboratories at the University of Washington Medical Center.Dr. Greninger is credited with developing one of the first tests to detect the coronavirus in the United States. But he is pessimistic that health systems can pivot quickly to sort out which patients have Delta or Omicron. And although a shortcut test can detect Omicron, there’s no simple way to report the results in bulk, he said.What’s more, the genome sequencing used by public health officials takes nearly a week — too long to target the early antibody treatments that have been found to reduce the need for hospitalizations. That makes patient care particularly difficult right now, said Dr. Mark Siedner, an infectious disease clinician and researcher at Massachusetts General Hospital.In Massachusetts and nearby states, an estimated 44.5 percent of cases are Omicron. Dr. Siedner said his health system has stopped using the Regeneron and Eli Lilly antibodies that are not effective against Omicron and are “anxiously awaiting” more doses of the effective treatment by GlaxoSmithKline and Vir Biotechnology.“We’re in a holding pattern and it’s a terrible time to be in that place,” he said.