Are rapid-result antigen tests an unappreciated long-range tool to tame COVID?
An overwhelming consensus on any topic is very rare these days. But many Americans, whatever their political leanings, seem to feel that the policies, communications, and actions of the public health “experts” and politicians about the COVID-19 pandemic have been confusing, sometimes contradictory, and in some cases, inconsistent with the scientific evidence.
Whether it was flip-flops on the effectiveness of masks, seemingly inane restrictions on certain activities, or baseless advocacy of ineffective drugs, the past 20 months have provided numerous reasons to question what we were told. In other cases, the absence of sufficient information has created opportunities for armchair experts to exhibit their lack of expertise.
There is a useful but misunderstood and underused mitigation tool – rapid-result antigen tests which detect pieces of the SARS-CoV-2 virus’s proteins – that can slow the spread of infections. Used properly, these tests can provide a method to screen workers while a campaign is mounted to depoliticize the vaccines, as well as to encourage the administration of booster shots in vulnerable (vaccinated) individuals.
The rapid-result antigen tests are a self-administered initial screening tool for individuals to use before they venture into situations where they might come into contact with vulnerable people. These tests can identify individuals who are in their three-to-five-day period of maximum contagiousness, mostly before they are symptomatic. They generally involve putting a nasal swab and some reagent drops on a test card or test cassette that quickly displays two lines for positive or one for negative. Results are available in 10-30 minutes, in contrast to the slightly more accurate PCR tests, which measure viral RNA but whose results take days to be reported.
In simple terms, the rapid antigen test enables you to be (pretty) sure you are not at risk to others before you leave for any get-together, movie, indoor sporting event, trip to a crowded store, and so on. These tests could become crucial yet simple to use, requiring little more time and effort than brushing your teeth before going out. It would also be useful for schoolchildren or teachers exposed to a case of COVID-19, by converting “test and quarantine” while awaiting the results of the PCR test, to “test and stay” if the test is negative.
It is important to note that rapid antigen testing (or PCR testing, for that matter) is not a substitute for vaccination. As Harvard epidemiologist and immunologist Michael Mina has observed, vaccination and rapid testing work in distinct and complementary ways: Vaccination has its greatest impact on preventing serious illness — but not spread — while testing has its greatest impact as a tool to help identify those likely to spread infection to others. On Twitter, he has described his routine when visiting his elderly parents: He tests himself in his car before entering their home, and then frequently during his visit.
So, where are these tests? They are readily available free in the U.K. but have come late to the U.S. market in large numbers because they have been treated as a highly regulated medical device rather than a public health tool. Regulators have thus compared them to lab-run PCR tests, which are more accurate over the entire course of an illness – though not necessarily much better during the period of maximum contagiousness – and deemed them inferior in function. If rapid tests are used appropriately, PCR is the wrong measuring stick. The result has been suppressed demand for the rapid antigen tests, and prices remain high in the U.S., about $7-$12 each – if you can find them at all. A few companies, such as Google, make rapid tests available to employees at little or no cost. But in Europe they can cost under one dollar to the general public (although we do not know whether government subsidies are involved).
There are obvious flaws in the regulators’ logic of treating these tests as devices subject to comparative evaluation. First, almost nobody electively opts to be tested if they don’t have symptoms, and thereby, if infected, can become spreaders as the virus replicates during the asymptomatic period. By contrast, if the cost were minimal, people could employ these rapid tests even in the absence of symptoms as a measure of personal responsibility at little inconvenience. Second, even if a person is PCR-tested, the results take days to be reported, and an infected person can be a spreader during that time. Third, even if the rapid antigen tests miss a few positives, it’s better to have most of those who self-screen and test positive remain at home than not to stop anybody at all. In other words, the rapid antigen test achieves the most important goal: limiting the number of person-days that asymptomatic but contagious people are at large, infecting others. This is discussed clearly and persuasively by Harvard Professor Mina in this video, starting about 33 minutes in.
The Biden administration seems finally to have awakened to the importance of these tests. In an effort to increase availability, the White House earlier this month allocated $1 billion to purchase millions of tests over the next year, encouraging manufacturers to ramp up production. But given the feds’ enormous expenditures on the pandemic over the past 20 months, and the toll that it continues to take on the nation’s health and economy, that is very little, very late.
Henry I. Miller, a physician and molecular biologist, is a Senior Fellow at the Pacific Research Institute. Find Henry on Twitter @henryimiller
Andrew I. Fillat spent his career in technology venture capital and information technology companies. He is also the co-inventor of relational databases.Read More
Je, vipimo vya haraka vya antigen ni chombo kisichokubaliwa cha muda mrefu cha kudhibiti COVID? Maelezo ya pamoja juu ya mada yoyote ni nadra sana siku hizi. "Wamarekani wengi, bila kujali mielekeo yao ya kisiasa, wanaonekana kuhisi kwamba sera, mawasiliano, na vitendo vya ""wataalamu"" wa afya ya umma na wanasiasa kuhusu janga la COVID-19 vimekuwa vya kuchanganyikiwa, wakati mwingine vinavyopingana, na katika visa vingine, havipatani na ushahidi wa kisayansi." Kama ilikuwa flip-flops juu ya ufanisi wa vinyago, vizuizi vya kuonekana vya kipumbavu juu ya shughuli fulani, au utetezi usio na msingi wa dawa zisizo na ufanisi, miezi ya 20 iliyopita imetoa sababu nyingi za kutilia shaka kile tulichoambiwa. Katika visa vingine, ukosefu wa habari ya kutosha umeunda fursa kwa wataalamu wa kiti cha mkono kuonyesha ukosefu wao wa utaalam. Kuna chombo muhimu lakini kisichojulikana na kinachotumiwa vizuri cha kupunguza - vipimo vya antigen vya matokeo ya haraka ambavyo hugundua vipande vya protini za virusi vya SARS-CoV-2 - ambavyo vinaweza kupunguza kuenea kwa maambukizo. Kwa kutumia vizuri, vipimo hivi vinaweza kutoa njia ya kuchunguza wafanyakazi wakati kampeni inapoanzishwa ili kuondoa siasa za chanjo, na pia kuhamasisha utoaji wa risasi za booster kwa watu walio hatarini (waliopigwa chanjo). Uchunguzi wa haraka wa antigen ni chombo cha kwanza cha uchunguzi wa kibinafsi kwa watu binafsi kutumia kabla ya kuingia katika hali ambapo wanaweza kuwasiliana na watu walio hatarini. Uchunguzi huu unaweza kutambua watu ambao wako katika kipindi cha siku tatu hadi tano cha kuambukiza kwa kiwango cha juu, hasa kabla ya dalili. Kwa kawaida, ni kuweka swab ya pua na matone ya reagent kwenye kadi ya mtihani au kaseti ya mtihani ambayo huonyesha haraka mistari miwili kwa chanya au moja kwa hasi. Matokeo yanapatikana katika dakika 10-30, tofauti na vipimo vya PCR, ambavyo hupima RNA ya virusi lakini matokeo yake huchukua siku kadhaa kuripotiwa. Kwa maneno rahisi, mtihani wa haraka wa antigen unakuwezesha kuwa na uhakika (kwa kiasi) kwamba hauna hatari kwa wengine kabla ya kuondoka kwa mkutano wowote, sinema, tukio la michezo ya ndani, safari ya duka lenye watu wengi, na kadhalika. Vipimo hivi vinaweza kuwa muhimu lakini rahisi kutumia, vikihitaji muda na juhudi kidogo zaidi ya kupiga mswaki meno yako kabla ya kwenda nje. "Kwa wanafunzi au walimu walio na kesi ya COVID-19, itakuwa muhimu kubadilisha ""kupima na kuwekwa karantini"" wakati wa kusubiri matokeo ya mtihani wa PCR, kuwa ""kupima na kukaa"" ikiwa mtihani ni hasi." Ni muhimu kutambua kwamba upimaji wa haraka wa antigen (au upimaji wa PCR, kwa jambo hilo) sio mbadala wa chanjo. "Mtaalamu wa magonjwa ya kuambukiza na kinga wa Harvard Michael Mina amesema, ""Kugunduliwa kwa chanjo na upimaji wa haraka hufanya kazi kwa njia tofauti na za ziada: chanjo ina athari kubwa zaidi ya kuzuia magonjwa mazito - lakini sio kuenea - wakati upimaji una athari kubwa kama chombo cha kusaidia kutambua wale ambao wanaweza kueneza maambukizi kwa wengine.""" Katika ukurasa wake wa Twitter, ameelezea jinsi anavyojifanya wakati wa kuwatembelea wazazi wake wazee: Anajijaribu mwenyewe katika gari lake kabla ya kuingia nyumbani kwao, na kisha mara nyingi wakati wa ziara yake. Kwa hiyo, majaribio hayo yako wapi? "Hizi ni vifaa vya matibabu vya kawaida nchini Uingereza, lakini zimekuja kwa marehemu kwenye soko la Marekani kwa idadi kubwa kwa sababu zimetendewa kama ""kifaa cha matibabu kilichodhibitiwa sana"" badala ya chombo cha afya ya umma." Kwa hivyo, wasimamizi wameilinganisha na vipimo vya PCR vya maabara, ambavyo ni sahihi zaidi katika kipindi chote cha ugonjwa - ingawa sio lazima kuwa bora zaidi wakati wa kipindi cha kuambukiza kwa kiwango cha juu - na kuiona kuwa ya chini katika kazi. Kwa hivyo, ikiwa vipimo vya haraka vinatumiwa kwa usahihi, PCR ni kipimo kibaya. Matokeo yake ni kwamba mahitaji ya vipimo vya haraka vya antigen yamepungua, na bei bado ni ya juu nchini Marekani, karibu $ 7 - $ 12 kila moja - ikiwa unaweza kuipata kabisa. Kampuni kadhaa, kama vile Google, zinafanya vipimo vya haraka kwa wafanyikazi kwa gharama ndogo au bila gharama. Lakini katika Ulaya wanaweza gharama chini ya dola moja kwa umma kwa ujumla (ingawa hatujui kama ruzuku ya serikali ni kushiriki). Kuna kasoro dhahiri katika mantiki ya wasimamizi wa kutibu vipimo hivi kama vifaa vinavyopaswa kutathmini kulinganisha. Kwanza, karibu hakuna mtu anayechagua kupimwa ikiwa hawana dalili, na hivyo, ikiwa wameambukizwa, wanaweza kuwa waenezaji wakati virusi vinavyozidi wakati wa kipindi cha asymptomatic. Kwa kulinganisha, ikiwa gharama ilikuwa ndogo, watu wangeweza kutumia vipimo hivi vya haraka hata bila dalili kama kipimo cha uwajibikaji wa kibinafsi kwa usumbufu mdogo. Hata kama mtu atafanyiwa PCR, matokeo ya uchunguzi huchukua siku kadhaa, na mtu aliyeambukizwa anaweza kueneza virusi wakati huo. Tatu, hata kama vipimo vya haraka vya antigen vinakosa chanya chache, ni bora kuwa na wengi wa wale wanaojitambua na kupima chanya wabaki nyumbani kuliko kutomzuia mtu yeyote. Kwa maneno mengine, mtihani wa haraka wa antigen unafikia lengo muhimu zaidi: kupunguza idadi ya siku za mtu kwamba watu wasio na dalili lakini wenye kuambukiza wako huru, wakiambukiza wengine. Hii ni kwa sababu ya kuelezea kwa uwazi na kwa uwazi kwa Profesa Mina, ambaye anafundisha katika Chuo Kikuu cha Harvard, na anaelezea kwa uwazi na kwa uwazi zaidi. Serikali ya Biden inaonekana hatimaye kuamka kwa umuhimu wa majaribio haya. Kwa lengo la kuongeza upatikanaji, White House mapema mwezi huu ilitoa bilioni 1 kununua mamilioni ya vipimo kwa mwaka ujao, ikiwatia moyo wazalishaji kuongeza uzalishaji. Lakini kwa kuzingatia gharama kubwa za serikali kwa janga hilo katika miezi 20 iliyopita, na athari zinazoendelea kuchukua kwa afya na uchumi wa taifa, hiyo ni kidogo sana, ni marehemu sana. Henry I. Miller, daktari na mwanabiolojia wa molekuli, ni Mshiriki Mkuu katika Taasisi ya Utafiti ya Pasifiki. "Hii ni kwa sababu ya ""Heri"" ya Andrew I. Fillett, ambaye aliishi katika kampuni ya teknolojia ya teknolojia ya teknolojia ya teknolojia ya teknolojia ya teknolojia." Yeye pia ni co-mvumbuzi wa database uhusiano.Soma Zaidi