Twindemic and tripledemic (or tridemic) are terms used during the

COVID-19 pandemic The COVID-19 pandemic, also known as the coronavirus pandemic, is an ongoing global pandemic of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The novel virus was first identi ...

, referring to the possibility of a severe

flu season Flu season is an annually recurring time period characterized by the prevalence of an outbreak of influenza (flu). The season occurs during the cold half of the year in each hemisphere. It takes approximately two days to show symptoms. Influen ...

happening alongside an increase in cases of

COVID-19 Coronavirus disease 2019 (COVID-19) is a contagious disease caused by a virus, the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The first known case was identified in Wuhan, China, in December 2019. The disease quickly ...

during the fall and winter of 2020 and 2021, as well as

respiratory syncytial virus Respiratory syncytial virus (RSV), also called human respiratory syncytial virus (hRSV) and human orthopneumovirus, is a common, contagious virus that causes infections of the respiratory tract. It is a negative-sense, single-stranded RNA virus. ...

in the winter of 2022. A consequence of a twindemic may be a mixture of two different infections in the same person at the same time. The term ''twindemic'' is a

portmanteau A portmanteau word, or portmanteau (, ) is a blend of wordstwin Twins are two offspring produced by the same pregnancy.MedicineNet > Definition of TwinLast Editorial Review: 19 June 2000 Twins can be either ''monozygotic'' ('identical'), meaning that they develop from one zygote, which splits and forms two em ...

" and " pandemic". __TOC__

History

The term was used by an August 2020 article from ''

The New York Times ''The New York Times'' (''the Times'', ''NYT'', or the Gray Lady) is a daily newspaper based in New York City with a worldwide readership reported in 2020 to comprise a declining 840,000 paid print subscribers, and a growing 6 million paid d ...

'' written by Jan Hoffman. In the article, Hoffman credited Dr. L.J. Tan of the Immunization Action Coalition as an "early promoter" of the possibility of a twindemic. After the publication of ''The Times''' article, several media outlets began to report on the possibility of a twindemic. Health experts responded to the threat of a possible twindemic by encouraging more people to get the

flu vaccine Influenza vaccines, also known as flu shots, are vaccines that protect against infection by influenza viruses. New versions of the vaccines are developed twice a year, as the influenza virus rapidly changes. While their effectiveness varies fr ...

. A twindemic did not occur during the flu season in late 2020 due to cases of the seasonal flu being at historic lows in the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territori ...

and globally. These low amount of flu cases were attributed to measures put in place to prevent COVID-19 from spreading, including face masks,

social distancing In public health, social distancing, also called physical distancing, (NB. Regula Venske is president of the PEN Centre Germany.) is a set of non-pharmaceutical interventions or measures intended to prevent the spread of a contagious dis ...

, and

hand washing Hand washing (or handwashing), also known as hand hygiene, is the act of cleaning one's hands with soap or handwash and water to remove viruses/bacteria/microorganisms, dirt, grease, or other harmful and unwanted substances stuck to the hands ...

. Health experts renewed concerns of a possible twindemic happening during the fall and winter of 2021 due to loosening restrictions. In April 2022,

Apoorva Mandavilli Apoorva Mandavilli is an American investigative journalist whose work has focused on medical science. During the COVID-19 pandemic, she joined ''The New York Times'' as a health and science writer. In the spring of 2019, she was writer-in-reside ...

of ''

'' speculated that a twindemic has not occurred because "exposure to one respiratory virus may put the body's immune defenses on high alert, barring other intruders from gaining entry into the airways. This biological phenomenon, called

viral interference Viral interference, also known as superinfection resistance, is the inhibition of viral reproduction caused by previous exposure of cells to another virus. The exact mechanism for viral interference is unknown. Factors that have been implicated a ...

, may cap the amount of respiratory virus circulating in a region at any given time." In the

, flu cases, hospitalizations and deaths were up from the previous flu season, but were still lower than the pre-pandemic average.

"Flurona"

In January 2022,

Israel Israel (; he, יִשְׂרָאֵל, ; ar, إِسْرَائِيل, ), officially the State of Israel ( he, מְדִינַת יִשְׂרָאֵל, label=none, translit=Medīnat Yīsrāʾēl; ), is a country in Western Asia. It is situated ...

reported, for the first time, a mixture of COVID-19 and influenza infections, colloquially known as "flurona". In

Brazil Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...

, four cases of the double infection have been identified, including a 16-year-old male from

Rio de Janeiro Rio de Janeiro ( , , ; literally 'River of January'), or simply Rio, is the capital of the state of the same name, Brazil's third-most populous state, and the second-most populous city in Brazil, after São Paulo. Listed by the GaWC as a ...

. In Fortaleza of Ceará state, two children, including a one-year-old child tested positive without complications, and also a 52-year-old man who did not need hospitalization. In

São Paulo São Paulo (, ; Portuguese for ' Saint Paul') is the most populous city in Brazil, and is the capital of the state of São Paulo, the most populous and wealthiest Brazilian state, located in the country's Southeast Region. Listed by the Ga ...

, the Secretariat of Health announced that its state had 110 cases in 2021. Flurona infections have also been reported in the United States, the

Philippines The Philippines (; fil, Pilipinas, links=no), officially the Republic of the Philippines ( fil, Republika ng Pilipinas, links=no), * bik, Republika kan Filipinas * ceb, Republika sa Pilipinas * cbk, República de Filipinas * hil, Republ ...

Hungary Hungary ( hu, Magyarország ) is a landlocked country in Central Europe. Spanning of the Pannonian Basin, Carpathian Basin, it is bordered by Slovakia to the north, Ukraine to the northeast, Romania to the east and southeast, Serbia to the ...

and

Romania Romania ( ; ro, România ) is a country located at the crossroads of Central, Eastern, and Southeastern Europe. It borders Bulgaria to the south, Ukraine to the north, Hungary to the west, Serbia to the southwest, Moldova to the east, and ...

References

2020 neologisms Impact of the COVID-19 pandemic Influenza {{COVID-19-stub