A healthcare worker vaccinates a man as part of the start of the seasonal flu vaccination campaign as a preventive measure due to the outbreak of coronavirus disease (COVID-19), in Beccar, on the outskirts of Buenos Aires, Argentina June 17, 2020. Picture taken June 17, 2020. REUTERS/Agustin Marcarian

A healthcare worker vaccinates a woman as part of the start of the seasonal flu vaccination campaign as a preventive measure due to the outbreak of coronavirus disease (COVID-19), in Beccar, on the outskirts of Buenos Aires, Argentina June 17, 2020. Picture taken June 17, 2020. REUTERS/Agustin Marcarian

A nurse prepares a vaccine as part of the start of the seasonal flu vaccination campaign as a preventive measure due to the outbreak of coronavirus disease (COVID-19), in Santiago, Chile, March 16, 2020. Picture taken March 16, 2020. REUTERS/Ivan Alvarado

A child receives a vaccination as part of the start of the seasonal flu vaccination campaign as a preventive measure due to the outbreak of coronavirus disease (COVID-19), in Santiago, Chile, March 16, 2020. Picture taken March 16, 2020. REUTERS/Ivan Alvarado

A healthcare worker vaccinates a woman as part of the start of the seasonal flu vaccination campaign as a preventive measure due to the outbreak of coronavirus disease (COVID-19), in Beccar, on the outskirts of Buenos Aires, Argentina June 17, 2020. Picture taken June 17, 2020. REUTERS/Agustin Marcarian

A child and his grandmother wear face masks as they hold their arms after receiving a vaccine as part of the start of the seasonal flu vaccination campaign as a preventive measure due to the outbreak of coronavirus disease (COVID-19), in Santiago, Chile, March 16, 2020. Picture taken March 16, 2020. REUTERS/Ivan Alvarado

A child receives a vaccination as part of the start of the seasonal flu vaccination campaign as a preventive measure due to the outbreak of coronavirus disease (COVID-19), in Santiago, Chile, March 16, 2020. Picture taken March 16, 2020. REUTERS/Ivan Alvarado

Robert Redfield, director of the Centers for Disease Control and Prevention (CDC), and Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, and other health officials testify before the House Energy and Commerce Committee in Washington, D.C., U.S., on Tuesday, June 23, 2020. Trump administration health officials will tell lawmakers that their agencies are preparing for a flu season that will be complicated by the coronavirus pandemic. Sarah Silbiger/Pool via REUTERS

Representative Frank Pallone, a Democrat from New Jersey, leads a House Energy and Commerce Committee hearing in Washington, D.C., U.S., on Tuesday, June 23, 2020. Trump administration health officials will tell lawmakers that their agencies are preparing for a flu season that will be complicated by the coronavirus pandemic. Sarah Silbiger/Pool via REUTERS

Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, testifies before the House Energy and Commerce Committee in Washington, D.C., U.S., on Tuesday, June 23, 2020. Trump administration health officials will tell lawmakers that their agencies are preparing for a flu season that will be complicated by the coronavirus pandemic. Sarah Silbiger/Pool via REUTERS

Representative David McKinley, a Republican from West Virginia, questions witnesses during a House Energy and Commerce Committee hearing in Washington, D.C., U.S., on Tuesday, June 23, 2020. Trump administration health officials will tell lawmakers that their agencies are preparing for a flu season that will be complicated by the coronavirus pandemic. Sarah Silbiger/Pool via REUTERS

Representative Michael Burgess, a Republican from Texas, questions witnesses during a House Energy and Commerce Committee hearing in Washington, D.C., U.S., on Tuesday, June 23, 2020. Trump administration health officials will tell lawmakers that their agencies are preparing for a flu season that will be complicated by the coronavirus pandemic. Sarah Silbiger/Pool via REUTERS

Representative Greg Walden, a Republican from Oregon and ranking member of the House Energy and Commerce Committee, listens during a House Energy and Commerce Committee hearing in Washington, D.C., U.S., on Tuesday, June 23, 2020. Trump administration health officials will tell lawmakers that their agencies are preparing for a flu season that will be complicated by the coronavirus pandemic. Sarah Silbiger/Pool via REUTERS

Robert Redfield, director of the Centers for Disease Control and Prevention (CDC), left, and Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, testify before the House Energy and Commerce Committee in Washington, D.C., U.S., on Tuesday, June 23, 2020. Trump administration health officials will tell lawmakers that their agencies are preparing for a flu season that will be complicated by the coronavirus pandemic. Sarah Silbiger/Pool via REUTERS

Robert Redfield, director of the Centers for Disease Control and Prevention (CDC), left, and Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, testify before the House Energy and Commerce Committee in Washington, D.C., U.S., on Tuesday, June 23, 2020. Trump administration health officials will tell lawmakers that their agencies are preparing for a flu season that will be complicated by the coronavirus pandemic. Sarah Silbiger/Pool via REUTERS

Stephen Hahn, commissioner of food and drugs at the U.S. Food and Drug Administration (FDA), testifies before the House Energy and Commerce Committee in Washington, D.C., U.S., on Tuesday, June 23, 2020. Trump administration health officials will tell lawmakers that their agencies are preparing for a flu season that will be complicated by the coronavirus pandemic. Sarah Silbiger/Pool via REUTERS

Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, testifies before the House Energy and Commerce Committee in Washington, D.C., U.S., on Tuesday, June 23, 2020. Trump administration health officials will tell lawmakers that their agencies are preparing for a flu season that will be complicated by the coronavirus pandemic. Sarah Silbiger/Pool via REUTERS

Brett Giroir, U.S. assistant secretary for health, is seen during a break from the House Energy and Commerce Committee hearing in Washington, D.C., U.S., on Tuesday, June 23, 2020. Trump administration health officials will tell lawmakers that their agencies are preparing for a flu season that will be complicated by the coronavirus pandemic. Sarah Silbiger/Pool via REUTERS

Robert Redfield, director of the Centers for Disease Control and Prevention (CDC), left, and Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, testify before the House Energy and Commerce Committee in Washington, D.C., U.S., on Tuesday, June 23, 2020. Trump administration health officials will tell lawmakers that their agencies are preparing for a flu season that will be complicated by the coronavirus pandemic. Sarah Silbiger/Pool via REUTERS

Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, returns from a break from the House Energy and Commerce Committee hearing in Washington, D.C., U.S., on Tuesday, June 23, 2020. Trump administration health officials will tell lawmakers that their agencies are preparing for a flu season that will be complicated by the coronavirus pandemic. June 23, 2020. Sarah Silbiger/Pool via REUTERS

The words of Avigan, an anti-flu drug that is being tested as a treatment for COVID-19 patients, are seen on a board displaying the treatment record at the Intensive Care Unit (ICU) ward for coronavirus disease (COVID-19) patients at St. Marianna Medical University Hospital in Kawasaki, south of Tokyo, Japan May 4, 2020. Picture taken May 4, 2020. REUTERS/Issei Kato

The words of Avigan, an anti-flu drug that is being tested as a treatment for COVID-19 patients, are seen on a board displaying the treatment record at the Intensive Care Unit (ICU) ward for coronavirus disease (COVID-19) patients at St. Marianna Medical University Hospital in Kawasaki, south of Tokyo, Japan May 4, 2020. REUTERS/Issei Kato

The Carnival Valor cruise ship, which is housing crew members only, is docked in its home port of New Orleans, Louisiana, U.S., amid the outbreak of the coronavirus disease (COVID-19), April 12, 2020. According to a Carnival Cruise Line representative, while some crew members were bussed to the airport and flew home on April 8, others are still on the ship have either been held up by travel restrictions, have tested positive for COVID-19 or are exhibiting signs of the flu, and therefore will not be allowed to leave the ship until they are healthy. REUTERS/Kathleen Flynn

The Carnival Valor cruise ship, which is housing crew members only, is docked in its home port of New Orleans, Louisiana, U.S., amid the outbreak of the coronavirus disease (COVID-19), April 12, 2020. According to a Carnival Cruise Line representative, while some crew members were bussed to the airport and flew home on April 8, others are still on the ship have either been held up by travel restrictions, have tested positive for COVID-19 or are exhibiting signs of the flu, and therefore will not be allowed to leave the ship until they are healthy. REUTERS/Kathleen Flynn?

Jesse Baum walks her dog in the Bywater neighborhood near the Mississippi river where the Carnival Valor cruise ship has been docked in New Orleans, Louisiana, U.S., amid the outbreak of the coronavirus disease (COVID-19), April 12, 2020. According to a Carnival Cruise Line representative, while some crew members were bussed to the airport and flew home on April 8, others are still on the ship have either been held up by travel restrictions, have tested positive for COVID-19 or are exhibiting signs of the flu, and therefore will not be allowed to leave the ship until they are healthy. REUTERS/Kathleen Flynn?

People are seen on the balconies of Carnival Valor cruise ship, which is housing crew members only, as it docks in its home port of New Orleans, Louisiana, U.S., amid the outbreak of the coronavirus disease (COVID-19), April 12, 2020. According to a Carnival Cruise Line representative, while some crew members were bussed to the airport and flew home on April 8, others are still on the ship have either been held up by travel restrictions, have tested positive for COVID-19 or are exhibiting signs of the flu, and therefore will not be allowed to leave the ship until they are healthy. REUTERS/Kathleen Flynn?

People are seen on the balconies of Carnival Valor cruise ship, which is housing crew members only, as it docks in its home port of New Orleans, Louisiana, U.S., amid the outbreak of the coronavirus disease (COVID-19), April 12, 2020. According to a Carnival Cruise Line representative, while some crew members were bussed to the airport and flew home on April 8, others are still on the ship have either been held up by travel restrictions, have tested positive for COVID-19 or are exhibiting signs of the flu, and therefore will not be allowed to leave the ship until they are healthy. REUTERS/Kathleen Flynn?

The Carnival Valor cruise ship, which is housing crew members only, is docked in its home port of New Orleans, Louisiana, U.S., amid the outbreak of the coronavirus disease (COVID-19), April 12, 2020. According to a Carnival Cruise Line representative, while some crew members were bussed to the airport and flew home on April 8, others are still on the ship have either been held up by travel restrictions, have tested positive for COVID-19 or are exhibiting signs of the flu, and therefore will not be allowed to leave the ship until they are healthy. REUTERS/Kathleen Flynn?

An Egyptian veterinarian administers an avian flu vaccination to a stork held by a zoo keeper at the closed Giza Zoo, during the spread of coronavirus disease (COVID-19) on the outskirts of Cairo, Egypt April 7, 2020. REUTERS/Amr Abdallah Dalsh TPX IMAGES OF THE DAY

An Egyptian veterinarian administers an avian flu vaccination to a Guinea Fowl held by a zoo keeper at the closed Giza Zoo, during the spread of coronavirus disease (COVID-19) on the outskirts of Cairo, Egypt April 7, 2020. REUTERS/Amr Abdallah Dalsh TPX IMAGES OF THE DAY

An Egyptian veterinarian and zoo keepers wear gloves for the semi-annual bird flu vaccination at the closed Giza Zoo, during the spread of coronavirus disease (COVID-19) on the outskirts of Cairo, Egypt April 7, 2020. REUTERS/Amr Abdallah Dalsh

An Egyptian veterinarian administers an avian flu vaccination to a Guinea Fowl held by a zoo keeper at the closed Giza Zoo, during the spread of coronavirus disease (COVID-19) on the outskirts of Cairo, Egypt April 7, 2020. REUTERS/Amr Abdallah Dalsh

An Egyptian veterinarian administers an avian flu vaccination to a duck held by a zoo keeper at the closed Giza Zoo, during the spread of coronavirus disease (COVID-19) on the outskirts of Cairo, Egypt April 7, 2020. REUTERS/Amr Abdallah Dalsh

An Egyptian veterinarian prepares an avian flu vaccination at the closed Giza Zoo, during the spread of coronavirus disease (COVID-19) on the outskirts of Cairo, Egypt April 7, 2020. REUTERS/Amr Abdallah Dalsh

An Egyptian veterinarian administers an avian flu vaccination to a chicken held by a zoo keeper at the closed Giza Zoo, during the spread of coronavirus disease (COVID-19) on the outskirts of Cairo, Egypt April 7, 2020. REUTERS/Amr Abdallah Dalsh

Chickens are seen as an Egyptian veterinarian administers an avian flu vaccination at the closed Giza Zoo, during the spread of coronavirus disease (COVID-19) on the outskirts of Cairo, Egypt April 7, 2020. REUTERS/Amr Abdallah Dalsh

An Egyptian veterinarian administers an avian flu vaccination to a duck held by a zoo keeper at the closed Giza Zoo, during the spread of coronavirus disease (COVID-19) on the outskirts of Cairo, Egypt April 7, 2020. REUTERS/Amr Abdallah Dalsh

An Egyptian veterinarian administers an avian flu vaccination to a pelican held by a zookeeper at the closed Giza Zoo, during the spread of coronavirus disease (COVID-19) on the outskirts of Cairo, Egypt April 7, 2020. REUTERS/Amr Abdallah Dalsh

Health agents arrive to vaccinate the Ribeirinhos (forest dwellers) against flu and H1N1, as advised by health officials to facilitate diagnosis for coronavirus, amid the coronavirus disease (COVID-19) outbreak, along the Negro River banks, in Manaus, Brazil, April 2, 2020. Picture taken April 2, 2020. REUTERS/Bruno Kelly

Health agents arrive to vaccinate the Ribeirinhos (forest dwellers) against flu and H1N1, as advised by health officials to facilitate diagnosis for coronavirus, amid the coronavirus disease (COVID-19) outbreak, along the Negro River banks, in Manaus, Brazil, April 2, 2020. Picture taken April 2, 2020. REUTERS/Bruno Kelly

A health agent vaccinates an elderly man against flu and H1N1, as advised by health officials to facilitate diagnosis for coronavirus, amid the coronavirus disease (COVID-19) outbreak, along the Negro River banks, where the Ribeirinhos (forest dwellers) live, in Manaus, Brazil, April 2, 2020. Picture taken April 2, 2020. REUTERS/Bruno Kelly

Health agents are seen in a boat before the vaccination of Ribeirinhos (forest dwellers) against flu and H1N1, as advised by health officials to facilitate diagnosis for coronavirus, amid the coronavirus disease (COVID-19) outbreak, along the Negro River banks, in Manaus, Brazil, April 2, 2020. Picture taken April 2, 2020. REUTERS/Bruno Kelly

Miami police officers remove journalists from an area as they report the arrival of sick crew members with flu-like symptoms from two cruise ships, the Costa Favolosa and Costa Magica at U.S. Coast Guard station at Port of Miami after the Florida Department of Health reported more than 2300 confirmed cases of coronavirus disease (COVID-19), in Miami, Florida U.S., March 26, 2020. REUTERS/Carlos Barria

First responders evacuate sick crew members with flu-like symptoms from two cruise ships, the Costa Favolosa and Costa Magica at U.S. Coast Guard station at Port of Miami after the Florida Department of Health reported more than 2300 confirmed cases of coronavirus disease (COVID-19), in Miami, Florida U.S., March 26, 2020. REUTERS/Carlos Barria TPX IMAGES OF THE DAY

First responders evacuate sick crew members with flu-like symptoms from two cruise ships, the Costa Favolosa and Costa Magica at U.S. Coast Guard station at Port of Miami after the Florida Department of Health reported more than 2300 confirmed cases of coronavirus disease (COVID-19), in Miami, Florida U.S., March 26, 2020. REUTERS/Carlos Barria

First responders evacuate sick crew members with flu-like symptoms from two cruise ships, the Costa Favolosa and Costa Magica at U.S. Coast Guard station at Port of Miami after the Florida Department of Health reported more than 2300 confirmed cases of coronavirus disease (COVID-19), in Miami, Florida U.S., March 26, 2020. REUTERS/Carlos Barria

First responders evacuate sick crew members with flu-like symptoms from two cruise ships, the Costa Favolosa and Costa Magica at U.S. Coast Guard station at Port of Miami after the Florida Department of Health reported more than 2300 confirmed cases of coronavirus disease (COVID-19), in Miami, Florida U.S., March 26, 2020. REUTERS/Carlos Barria

First responders evacuate sick crew members with flu-like symptoms from two cruise ships, the Costa Favolosa and Costa Magica at U.S. Coast Guard station at Port of Miami after the Florida Department of Health reported more than 2300 confirmed cases of coronavirus disease (COVID-19), in Miami, Florida U.S., March 26, 2020. REUTERS/Carlos Barria

First responders evacuate sick crew members with flu-like symptoms from two cruise ships, the Costa Favolosa and Costa Magica at U.S. Coast Guard station at Port of Miami after the Florida Department of Health reported more than 2300 confirmed cases of coronavirus disease (COVID-19), in Miami, Florida U.S., March 26, 2020. REUTERS/Carlos Barria

First responders evacuate sick crew members with flu-like symptoms from two cruise ships, the Costa Favolosa and Costa Magica at U.S. Coast Guard station at Port of Miami after the Florida Department of Health reported more than 2300 confirmed cases of coronavirus disease (COVID-19), in Miami, Florida U.S., March 26, 2020. REUTERS/Carlos Barria

Products for flu and virus prevention are displayed at Pharmaca Integrative Pharmacy, which sells natural and integrative wellness solutions, amid the coronavirus disease (COVID-19) outbreak in Seattle, Washington, U.S., March 24, 2020. REUTERS/Brian Snyder

Products for flu and virus prevention are displayed at Pharmaca Integrative Pharmacy, which sells natural and integrative wellness solutions, amid the coronavirus disease (COVID-19) outbreak in Seattle, Washington, U.S., March 24, 2020. REUTERS/Brian Snyder

Army nurses and Red Cross members listen orientations to attend the vaccination against the flu, as advised by health officials to facilitate diagnosis for coronavirus, amid the coronavirus disease (COVID-19) outbreak, in Rio de Janeiro, Brazil, March 24, 2020. REUTERS/Sergio Moraes

Army nurses listen orientations to attend the vaccination against the flu, as advised by health officials to facilitate diagnosis for coronavirus, amid the coronavirus disease (COVID-19) outbreak, in Rio de Janeiro, Brazil, March 24, 2020. REUTERS/Sergio Moraes

Army nurses listen orientations to attend the vaccination against the flu, as advised by health officials to facilitate diagnosis for coronavirus, amid the coronavirus disease (COVID-19) outbreak, in Rio de Janeiro, Brazil, March 24, 2020. REUTERS/Sergio Moraes

A Red Cross member arrives to attend the orientations of the vaccination against the flu, as advised by health officials to facilitate diagnosis for coronavirus, amid the coronavirus disease (COVID-19) outbreak, in Rio de Janeiro, Brazil March 24, 2020 REUTERS/Sergio Moraes

A woman walks after getting vaccinated against the flu, as advised by health officials to facilitate diagnosis for coronavirus, amid the coronavirus disease (COVID-19) outbreak, in Brasilia, Brazil March 23, 2020 REUTERS/Ueslei Marcelino

A health worker vaccinates a woman against the flu, as advised by health officials to facilitate diagnosis for coronavirus, amid the coronavirus disease (COVID-19) outbreak, in Brasilia, Brazil March 23, 2020 REUTERS/Ueslei Marcelino TPX IMAGES OF THE DAY

People stand in line before getting vaccinated against the flu, as advised by health officials to facilitate diagnosis for coronavirus, amid the coronavirus disease (COVID-19) outbreak, in Brasilia, Brazil March 23, 2020 REUTERS/Ueslei Marcelino