COVID-19: Track the latest developments and look back at how the pandemic evolved

Timeline will be updated as new information is announced.

It's challenging to keep up with the latest developments in the COVID-19 pandemic and the vaccines being created to end it. Whether it’s the number of cases and deaths, changes in local and state guidelines, or which vaccine is available and for whom - new information is arriving frequently.

This timeline, which is being updated often, will help you keep track of the latest developments.

Get the latest COVID-19 vaccine information at uclahealth.org/vaccine.

For more coronavirus information & FAQs, visit uclahealth.org/coronavirus.


APRIL

April 16: While emphasizing the efficacy of current COVID-19 vaccines, federal officials say they are beginning to develop a "next generation of vaccines" directed at emerging variants. Executives from Pfizer, Moderna and Johnson & Johnson say regular vaccine boosters against the virus are likely.

April 15: All California residents age 16 or older are now eligible to get a COVID-19 vaccine. In Southern California, residents in this age group in Los Angeles, San Diego, Riverside, San Bernardino, Santa Barbara and San Luis Obispo counties already were eligible.

April 13: Los Angeles County health officials say they are heeding the recommendations of the Centers for Disease Control and Prevention and U.S. Food and Drug Administration and will pause use of the Johnson & Johnson vaccine countywide until the federal agencies complete a safety review of the shot. Vaccine providers in the county will contact people who had been scheduled to get the single-dose Johnson & Johnson vaccine about rescheduling or offering appointments for the two-dose Pfizer or Moderna vaccines.

CDC and FDA recommend a pause in the distribution of the Johnson & Johnson COVID-19 vaccine after six reported U.S. cases of blood clots potentially linked to the one-dose vaccine. More than 6.8 million doses have been administered in the U.S. A CDC advisory council will study the cases further to determine how to proceed long term. At the same time, Johnson & Johnson announced it would "proactively delay the rollout" of the vaccine in Europe. Though the clotting reaction to the Johnson & Johnson vaccine is extremely rare, patients who received the vaccine within the last three weeks should look for symptoms of these unusual clots, health officials say. Symptoms may include severe headache, abdominal or leg pain or shortness of breath. Those experiencing such symptoms should contact their health care provider or dial 211 to be connected to a medical expert.

April 9: Emerging from its first full-season closure in 98 years, the Hollywood Bowl announces plans to reopen May 15 with a free concert for frontline workers including health care personnel, grocery-store employees and delivery drivers.

April 6: State officials announce plans to fully reopen the California economy on June 15 if COVID-19 cases and hospitalizations remain low, adding that mask mandates will persist for the foreseeable future.

April 2: Los Angeles County public health officials announce that COVID-19 cases have declined sufficiently to move into the orange tier, which allows for additional businesses to reopen or expand operations, beginning Monday, April 5. Bars that do not serve meals may reopen for outdoor service; breweries, wineries and distilleries can open indoors at 25% capacity; restaurants can increase indoor capacity to 50% or 200 people, whichever is fewer; places of worship can expand indoor services to 50% capacity; movie theaters can increase capacity to 50% or 200 people, whichever is fewer; fitness centers can operate indoors at 25% capacity; hair salons, barbershops and personal-care services can operate at 75% capacity; museums, zoos and aquariums can open indoors at 50% capacity. Masking and social-distancing requirements will still apply at all of these locations.

California State Department of Public Health announces that indoor concerts, theater performances and other events will resume April 15. Guests will need to test COVID-19 negative on site or show proof of full vaccination to enter. Venue capacity will depend on individual counties, which are in different reopening tiers based on COVID-19 transmission rates.

CDC revises its travel guidelines, saying those who are fully vaccinated against COVID-19 can now travel domestically, providing they continue to wear face coverings, physically distance and wash their hands to protect others. A person is considered fully vaccinated two weeks after the second of the two-dose Pfizer or Moderna vaccine, or after the one dose of the single-shot Johnson & Johnson vaccine. For international travel, the CDC says those who are fully vaccinated should still get tested three to five days after travel, but do not need to get tested prior to leaving the U.S., unless it's required by the destination. International travelers don't need to self-quarantine after returning to the U.S. Like domestic travelers, international travelers should continue to practice safety measures.

April 1: Pfizer reports that its COVID-19 vaccine remains effective for at least six months after the second dose, based on results of its ongoing clinical trial.

MARCH

March 31: COVID-19 was the third-leading cause of death in 2020 in the U.S., behind only heart disease and cancer, the CDC reports based on data still being finalized. COVID-19 was reported as the cause, or a contributing cause, of death for 377,883 people. Heart disease caused 690,882 deaths and cancer, 598,932 deaths.

Pfizer reports its two-dose COVID-19 vaccine was 100% effective in a study of children ages 12-15 and plans to submit to the FDA for expanded emergency use authorization. The vaccine is currently available in the U.S. for people age 16 and older.

March 29: President Joe Biden says 90% of adults in the U.S. will be eligible for the COVID-19 vaccine by April 19, sooner than the original May 1 plan. The president also announced that the number of pharmacies in the federal vaccine distribution program will climb from 17,000 to 40,000 locations and that 33 million vaccine doses will be made available this week.

Federal health researchers report that the two-dose COVID-19 vaccine regimen from both Pfizer and Moderna prevent 90% of coronavirus infections two weeks after the second shot. A single dose of either vaccine was shown to prevent 80% of infections two weeks after vaccination. Researchers found both vaccines also offer effective protection against variant strains circulating in the U.S.

March 25: California Gov. Gavin Newsom announces that all California residents age 16 or older will be able to get a COVID-19 vaccine beginning April 15. Residents age 50 or older will be eligible for vaccination April 1.

President Joe Biden announces a new goal of distributing 200 million doses of COVID-19 vaccine during his first 100 days in office. Biden's original goal of having 100 million vaccine doses administered during his first 100 days was reached last week, on his 59th day in office.

March 19: CDC adjusts its physical-distancing guidelines for classrooms, saying students can be at least three feet apart, not six, providing they are wearing masks. Middle school and high school students can be within three feet as well, providing there is no high level of COVID-19 spread within the community. The CDC still advises six feet of distancing between adults and students, and among students in communal areas and while eating, when masks will be off.

March 17: Disneyland announces plans to reopen on April 30, to limited capacity. So far, guidelines limit admission to California residents only. The Grand California hotel, on Disneyland grounds, will open April 29.

March 12: The California Dept. of Public Health announces that 2 million doses of the COVID-19 vaccine have been administered to people in the state's most under-resourced communities, a milestone that will allow Los Angeles and 12 other counties to move into the less-restrictive red tier of closures. Among the changes to be allowed effective March 15 in L.A. County are the return to in-person schooling for grades 7 to 12; opening of movie theaters and indoor dining at restaurants at 25% capacity; opening of retail and personal care services at 50% capacity; and opening of gyms, fitness centers and yoga and dance studios at 10% capacity.

The Pfizer COVID-19 vaccine arrives at UCLA Health. (Photo by Ann Johannson)

March 11: President Biden announces that he is directing all states, tribes and territories to make every adult eligible to be vaccinated against COVID-19 by May 1. "July 4 with your loved ones is the goal," he says.

March 9: Disneyland announces it's plan to re-open in late April, as COVID-19 cases continue to decline. No exact date was given.

March 8: The CDC issues new guidelines for people who are fully vaccinated against COVID-19, saying it's OK to gather indoors with other fully vaccinated people without wearing a mask or physically distancing. However, the CDC still advises fully vaccinated people to continue to wear masks and keep physically distanced when out in public, and to avoid large- or medium-size crowds. The CDC says fully vaccinated people may also gather, unmasked, with non-vaccinated people in the same household as long as the latter are at low risk for severe disease. Fully vaccinated is defined by the CDC as being two weeks past the second dose of the Pfizer or Moderna vaccines or of the single dose of the Johnson & Johnson vaccine.

March 5: California health officials announce that outdoor sports, live performances and theme parks will be allowed to reopen with limited capacity, to in-state visitors only, as soon as April 1 in counties reporting fewer than seven new daily COVID-19 cases per 100,000 residents. Capacities can increase as cases decline.

March 4: California officials say 40% of vaccine doses will be directed to the state's most vulnerable areas to inoculate residents at highest risk of COVID-19 infection and to speed reopening of the economy. About 8 million people in 400 ZIP codes - including many in Los Angeles County and the Central Valley - will be eligible for the newly allocated shots.

March 2: President Biden says there will be enough COVID-19 vaccine available for every American adult by the end of May, following the announcement of a partnership between Merck and Johnson & Johnson to speed up production.

FEBRUARY

Feb. 27: FDA grants emergency use authorization (EUA) for Johnson & Johnson's COVID-19 vaccine. It's the first single-dose coronavirus vaccine available in the U.S.

Feb. 23: Los Angeles County surpasses 20,000 COVID-19 deaths.

Feb. 22: The U.S. surpasses 500,000 COVID-19 deaths.

Feb. 16: Schools for students in grades pre-kindergarten through sixth are eligible to reopen in Los Angeles County. Twelve school districts, including Los Angeles Unified, have submitted required paperwork and have been approved to reopen, though exact reopening dates will be determined by individual school communities, according to Los Angeles County Public Health Director Dr. Barbara Ferrer.

County health officials announce that educators, emergency responders and workers in childcare, food service and agriculture will be eligible for vaccination beginning March 1.

Feb. 12: The CDC calls for K-12 schools to reopen, providing science-based guidelines for doing so safely that include universal mask-wearing, social distancing, frequent hand washing, cleaning and ventilating school facilities and contact tracing. How quickly schools can open depends on a community's daily new COVID-19 case count and the percentage of positive tests over a certain time period.

California health officials announce that people between the ages of 16 and 64 who are disabled or at high risk for mortality or morbidity from COVID-19 will be eligible to be vaccinated beginning March 15. Conditions for eligibility include cancer, chronic kidney disease above stage four, immunocompromised organ-transplant recipients, coronary artery disease, type II diabetes, Down syndrome and severe obesity.

Feb. 11: The coronavirus variant first identified in South Africa is identified in two California patients.

CVS Health announces that its pharmacies in California will begin distributing COVID-19 vaccines on Feb. 12.

Feb. 4: Johnson & Johnson submits an application to the FDA seeking emergency use authorization (EUA) for its single-dose COVID-19 vaccine.

COVID-19 deaths in the U.S. top 450,000.

Feb. 3: The federal COVID-19 task force announces it will open two new community vaccination sites in California, including one on the campus of Cal State Los Angeles. The sites in Los Angeles and Oakland will be staffed by workers from the Federal Emergency Management Agency and the Department of Health and Human Services.

Feb. 1: CDC begins requiring masks be worn when traveling by bus, subway, taxi, ride-share, plane, ship or ferry. The mask requirement, which goes into effect at 11:59 p.m., also applies to anyone inside an airport, train station, bus station and any other transportation hub.

JANUARY, 2021

Jan. 29: European Union drug regulators authorize use of the COVID-19 vaccine developed by AstraZeneca.

Jan. 28: A COVID-19 variant originally identified in South Africa has been diagnosed in the U.S. for the first time, in two cases in South Carolina, health officials announce.

Jan. 26: The number of confirmed COVID-19 cases globally tops 100 million.

Jan. 25: Gov. Newsom cancels the state's stay-at-home order, which he instituted Dec. 3. Los Angeles County officials respond by announcing numerous changes, among them the opening of personal care services, such as hair salons, at 25% capacity beginning today. Restaurants will be allowed to offer outdoor dining service starting Jan. 29.

Jan. 24: U.S. surpasses 25 million confirmed COVID-19 cases.

Jan. 23: Los Angeles County surpasses 15,000 COVID-19 deaths since the start of the pandemic.

Jan. 21: President Biden announces a national strategy for COVID-19 response that includes support from the Federal Emergency Management Agency (FEMA) which will establish vaccination centers, train vaccinators and serve as liaisons for each state; directives to the departments of Education and Health and Human Services to provide guidance and resources to reopen schools and childcare centers; the establishment of a COVID-19 testing board; mandatory testing and quarantine for travelers coming to the U.S. from other countries; and a request that all Americans wear masks for the next 100 days, which Biden calls "a patriotic act" that can save 50,000 lives.

Jan. 20: On his first day in office, President Biden signs executive orders requiring masks and physical distancing at all federal buildings and lands, including national parks and forests; establishing a federal COVID-19 coordinator; and restoring the National Security Council's global health security team.

Jan. 19: U.S. death toll from COVID-19 tops 400,000.

California tops 3 million confirmed COVID-19 cases.

Los Angeles County Public Health officials announce the opening of five new large-scale vaccination sites, including The Forum in Inglewood, Fairplex in Pomona and Six Flags Magic Mountain in Valencia.

Jan. 16: Los Angeles County surpasses 1 million cases of COVID-19.

Jan. 15: The worldwide COVID-19 death toll tops 2 million.

Jan. 14: Calling the U.S. vaccine rollout "a dismal failure," president-elect Joe Biden pledges to commit $400 billion to fight the pandemic, including the administration of 100 million vaccine doses during his first 100 days in office and the opening of most kindergarten-through-eighth-grade schools during that same period.

Jan. 13: The U.S. reaches 4,400 COVID-19 deaths in a single day.

Jan. 12: U.S. Centers for Disease Control and Prevention (CDC) announces that, beginning Jan. 26, all international airline passengers bound for the United States must be tested for coronavirus within three days of their departure and show proof of negative results before boarding their flight.

Federal government tells states to begin vaccinating all Americans age 65 and older to help stem the surge of COVID-19 cases, adding that vaccine supply held in reserve to provide required second doses will be released immediately.

Jan. 11: Los Angeles County Public Health Director Barbara Ferrer advises essential workers – those who leave their home daily for work – as well as people who regularly run errands for family, to wear masks inside their own homes to avoid spreading COVID-19 to family members.

Jan. 7: U.S. surpasses 4,000 daily COVID-19 deaths.

Jan. 6: U.S. reports a daily record 3,964 COVID-19 deaths.

Jan. 4: Britain announces a nationwide lockdown amid a spike in COVID-19 cases linked to the mutated strain.

Jan. 3: Total of U.S. deaths from COVID-19 surpasses 350,000.

Jan. 2: Los Angeles County tops 800,000 confirmed cases of COVID-19. It took 10 months to reach 400,000, on Nov. 30, but just more than a month to double that total.

Jan. 1: U.S. surpasses 20 million confirmed cases of COVID-19 since the beginning of the pandemic.

DECEMBER

Dec. 30: Los Angeles County surpasses 10,000 COVID-19 deaths since the start of the pandemic.

Gov. Newsom says the mutated coronavirus strain responsible for the majority of new COVID-19 infections in the U.K. has been identified in Southern California.

Britain becomes the first country to grant emergency use authorization to the COVID-19 vaccine developed by drug maker AstraZeneca and the University of Oxford.

Dec. 29: California health officials announce the stay-at-home order for Southern California and the San Joaquin Valley will remain in effect as ICU beds remain exceedingly scarce. The order will be in effect for at least three weeks.

A mutated strain of the coronavirus responsible for the majority of new COVID-19 infections in the U.K. is identified in the U.S. for the first time, in a Denver patient.

Dec. 23: Pfizer and BioNTech reach an agreement with the U.S. government to supply the country with 100 million more doses of their COVID-19 vaccine by the end of July.

Dec. 22: Los Angeles County surpasses 9,000 confirmed COVID-19 deaths.

Dec. 21: France and other members of the European Union restrict travelers from Britain over fears that a more-transmissible variant of coronavirus is spreading through London and surrounding areas.

Dec. 18: The U.S. Food and Drug Administration grants emergency use authorization to the COVID-19 vaccine from Moderna, with doses expected to ship immediately. 

U.S. tops 17.2 million confirmed COVID-19 cases.

Dec. 17: An FDA advisory panel, made up of scientists and infectious disease specialists, recommends the approval of the Moderna COVID-19 vaccine.

Dec. 16: UCLA Health begins administering Pfizer vaccines to health care workers.

Dec. 15: Pfizer vaccines begin arriving at UCLA Health.

In a review posted online, the U.S. Food and Drug Administration praises the efficacy and safety of the Moderna COVID-19 vaccine. A panel of experts is expected to advise the FDA, Thursday, on whether to grant emergency use authorization to the vaccine.

Dec. 14: First COVID-19 vaccine is administered, at Long Island Jewish Medical Center in Queens, N.Y. The US death toll from COVID-19 surpasses 300,000.

Dec. 13: Western States Scientific Safety Review Workgroup confirms safety and efficacy of the Pfizer COVID-19 vaccine, allowing distribution to go forward in California, Nevada, Oregon and Washington.

Dec. 12: Trucks stocked with the Pfizer vaccine begin rolling out for delivery to nearly 150 sites across the country.

Dec. 11: The FDA approves emergency use authorization for Pfizer's COVID-19 vaccine, allowing nationwide distribution to begin.

Dec. 10: A panel of scientists and infectious disease specialists that advises the FDA formally recommends that the agency grant emergency use authorization to the Pfizer vaccine.

Dec. 8: The U.S. tops 15 million confirmed COVID-19 cases. The U.K. delivers its first COVID-19 vaccine, manufactured by Pfizer/BioNTech. It's the first vaccine given outside of a clinical trial.

Dec. 7: Los Angeles Unified School District Superintendent Austin Beutner announces that schools will close on Dec. 10 for the remainder of 2020. This move will affect the 1% of L.A. Unified students, about 4,000, who have been receiving services on campus, including kindergarteners and students with special needs. Classes for all students will continue online.

Gov. Newsom announces a statewide, voluntary cellphone-based program launching Dec. 10 that notifies residents if a recent close contact has tested positive for COVID-19.

Dec. 6: ICU bed capacity of less than 15% in Southern California and the San Joaquin Valley trigger the state's three-week stay-at-home order for both regions, effective at 11:59 p.m.

Dec. 3: Gov. Newsom announces a modified 21-day statewide shutdown targeting counties facing shortages of hospital beds and other critical care services. President-elect Biden tells CNN he plans to ask Americans to wear masks for his first 100 days in office.

Dec. 2: The U.S. reports its largest single-day COVID-19 death toll since the start of the pandemic: more than 3,000. Britain issues emergency authorization for the Pfizer vaccine.

Dec. 1: The Advisory Committee for Immunization Practices advises the CDC that health care workers and residents of long-term care facilities should be first in line for COVID-19 vaccines in the U.S.


NOVEMBER

Nov. 30: Moderna seeks emergency use authorization from the FDA for its COVID-19 vaccine. Confirmed COVID-19 cases in the U.S.: More than 13.4 million.

Nov. 23: AstraZeneca announces that early data show its COVID-19 vaccine to be at least 70% effective. Confirmed COVID-19 cases in the U.S: 12.4 million.

Nov. 20: Pfizer seeks emergency use authorization from the FDA for its COVID-19 vaccine.

Nov. 18: The U.S. surpasses 250,000 COVID-19 deaths.

Nov. 17: The FDA authorizes the first at-home, prescription coronavirus test.

Nov. 16: Moderna reports preliminary data show COVID-19 vaccine is more than 94% effective.

Gov. Newsom orders most non-essential businesses statewide to close and health officials say Californians must wear masks outside their homes.

Nov. 15: There are more than 11 million confirmed COVID-19 cases in the U.S.

Nov. 13: The U.S. adds more than 184,000 confirmed COVID-19 cases, the fourth consecutive day the country has set a record for daily infection diagnoses.

Nov. 12: California surpasses 1 million diagnosed COVID-19 cases.

Nov. 9: Pfizer announces preliminary results of its vaccine tests that indicate it’s 90% effective in preventing COVID-19. There are 10 million confirmed coronavirus cases in the U.S.

Nov. 8: Diagnosed COVID-19 cases worldwide top 50 million.


OCTOBER

Oct. 22: Remdesivir becomes the first drug approved by the FDA to treat COVID-19.

Oct. 1: President Donald Trump announces he has tested positive for coronavirus.


SEPTEMBER

Sept. 28: The worldwide coronavirus death toll tops 1 million.

Sept. 22: The coronavirus death toll in the U.S. tops 200,000.


AUGUST

Aug. 31: The U.S. reports more than 6 million diagnosed COVID-19 cases. California reports 700,000.

Aug. 10: There are more than 20 million coronavirus cases worldwide, with more than 5 million in the U.S.

Aug. 7: California reports more than 10,000 COVID-19 deaths.


JULY

July 27: Pfizer and Moderna begin large-scale trials of potential COVID-19 vaccines with around 30,000 volunteers each.

July 13: Gov. Newsom orders all bars to close statewide, along with indoor dining and movie theaters.

July 11: The World Health Organization acknowledges that airborne transmission of coronavirus is possible.


JUNE

June 29: Los Angeles County officials announce beaches will be closed for the July 4 holiday weekend. The county becomes the first in the nation to announce 100,000 coronavirus diagnoses.

June 18: Gov. Newsom issues a statewide mask mandate.

Thermal camera installed at entrance to UCLA Health medical building.

June 16: UCLA Health installs thermal cameras at medical-building entrances to quickly scan for fevers.

June 1: Los Angeles County allows restaurants and hair salons to reopen for some in-person services.


MAY

May 6: UCLA Health begins in-house serology testing for COVID-19.

May 1: Remdesivir receives emergency use authorization to treat hospitalized COVID-19 patients.


APRIL

April 16: UCLA Health implements universal masking.

April 3: CDC and White House Coronavirus Task Force recommend Americans use face coverings in public.

Universal masking procedures

April 1: Gov. Newsom announces California schools will be closed for the remainder of the academic year.


MARCH

March 31: UCLA Health begins involvement in clinical trials for COVID-19 treatments.

March 27: Los Angeles County beaches close. Disneyland and Disney World close.

March 19: Gov. Newsom issues statewide shelter-in-place order, the first in the nation. Los Angeles Mayor Eric Garcetti announces “safer at home” order for the city and county. Most retail businesses, other than those deemed essential, are closed.

March 13: President Trump declares national emergency. Los Angeles Unified School District announces school closures beginning March 16.

COVID-19 virus rendering

March 12: Major League Soccer and National Hockey League suspend their seasons. Major League Baseball suspends Spring Training and delays opening day.

March 11: WHO declares coronavirus a pandemic. President Trump bans travelers from parts of Europe from entering the U.S. for 30 days. NBA suspends season. Public health officials announce first coronavirus death in Los Angeles County.

March 10: UCLA Health implements in-house testing for COVID-19. UCLA campus moves to online instruction.

March 4: Gov. Newsom declares a state of emergency in California. Los Angeles County declares state of emergency. UCLA Health convenes COVID-19 command center.

March 3: CDC says face-mask use in public is not recommended.


FEBRUARY

Feb. 26: First case of local transmission in the U.S. is a Northern California resident who did not travel or have contact with anyone known to have coronavirus.

Feb. 11: WHO renames novel coronavirus COVID-19.

Feb. 6: A California woman dies, later confirmed from coronavirus — the first coronavirus death in the U.S.


JANUARY

Jan. 31: U.S. Health and Human Services secretary Alex Azar declares a national public health emergency.

Jan. 30: World Health Organization declares “public health emergency of international concern” for only the sixth time in its history.

Jan. 25: CDC confirm California’s first coronavirus case: an Orange County patient who was a traveler from Wuhan, China. It’s the third case in the U.S.


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