Undiagnosed Ebola virus infection was probably very rare in international workers who were deployed during the 2013-2015 outbreak of the virus in West Africa, despite mild and asymptomatic cases of Ebola being known to occur, according to new research published in the journal PLOS Medicine.
As part of the study, more than 250 UK and Ireland healthcare and other workers were tested for Ebola virus antibodies after returning from West Africa -- no evidence of missed infections was found. This suggests that the vast majority of volunteers were kept safe by Personal Protective Equipment (PPE) and the Ebola treatment centre procedures in place. However, the study also found that potentially avoidable events putting frontline workers at risk of infection were quite common during the outbreak, with one in six participants classified as having 'near miss' exposure events.
In what is believed to be the first study of the prevalence of Ebola infection in international responders the research team, led by the London School of Hygiene & Tropical Medicine and funded by the Wellcome Trust, enrolled 300 UK and Ireland healthcare and other frontline workers¹ for the study and sent them oral fluid collection devices. Among the 268 respondents who returned their samples, 99% showed negative results on an antibody test which the authors had already proved gave very accurate results in Sierra Leone2. The remaining two people, who had no known exposure or symptoms, had positive results, but follow-up testing using different methods was negative, making Ebola virus infection very unlikely.The research team, led by the London School of Hygiene & Tropical Medicine and funded by the Wellcome Trust, enrolled 300 UK and Ireland healthcare and other frontline workers¹ for the study and sent them oral fluid collection devices. Among the 268 respondents who returned their samples, 99% showed negative results on an antibody test which the authors had already proved gave very accurate results in Sierra Leone2. The remaining two people, who had no known exposure or symptoms, had positive results, but follow-up testing using different methods was negative, making Ebola virus infection very unlikely.
Lead author Dr Catherine Houlihan from the London School of Hygiene & Tropical Medicine and UCL said: "The 2013-2015 Ebola outbreak was unprecedented -- the commitment and bravery of those who volunteered saved many lives. We know a small number of international health workers were infected with the virus but we thought it was possible that some infections had been missed, as we know asymptomatic or unrecognised infections can occur. However, our research suggests undetected infection in this group is, at most, a very rare event, and that the Personal Protective Equipment did its job well."
Participants, who included clinicians, laboratory workers and epidemiologists, also completed an online survey which asked if they experienced possible exposure to Ebola virus while in West Africa. Using 268 respondents' descriptions, 16% (43 people) were identified as having 'near miss' exposure events.
27 respondents reported experiencing very low-risk incidents³ such as having a facemask dislodged. Ten were identified as having low-risk exposure events which were classified as having direct physical contact with an Ebola patient who does not have vomiting, diarrhea, or bleeding. Five faced an intermediate risk incident with one respondent reporting 'being vomited on while wearing just gloves' and not full PPE, and one experienced the high-risk incident of a 'sharp injury with a broken vial of medication inside the 'red zone' with dirty and contaminated gloves'. The antibody tests showed that none of these individuals had any evidence of infection with Ebola.
Participants reported PPE suits torn by catching on doorways or corners, PPE breaches in Ebola laboratories, such as torn outer gloves, as well as the additional anxiety and distress these incidents caused them.
Dr Catherine Houlihan said: "The scale of the outbreak meant frontline workers faced demanding and draining circumstances. Participants have given crucial insights which provide valuable lessons for future Ebola outbreaks. Regular debriefing after work in the clinical red zone or laboratory, and blame-free reporting of near misses, should be part of routine practice in emergency treatment response work. Simple changes such as banning glass vials in the red zone could reduce the number of staff experiencing skin lacerations, and further testing of the robustness and fit of PPE suits, could potentially save health workers' lives in the future."
Participants, who were based mostly in Sierra Leone, were also asked whether they experienced fever or diarrhoea while in West Africa or within one month of their return, and if so whether they were tested for Ebola virus at the time. Despite symptoms in 21% (57/268) of the respondents, 70% were not tested, with those still in West Africa much less likely to receive a test -- 11 out of 17 who fell ill on their return were tested, but just one person out of 21 who fell ill in West Africa was tested.
Dr Houlihan said: "This study provides reassuring evidence about the lack of Ebola infection in individuals who had not previously been tested for the virus. However, the high proportion of health workers who didn't get tested when falling ill in West Africa, coupled with returnees' potential exposure to Ebola, are a concern. Although we don't know how many health workers reported being ill and were assessed to decide if they needed to be tested, protocols for the management of possible exposure to the virus, and for the management of illness, may need reviewing and to be standardised across organisations that deploy staff to outbreaks.
"Importantly, these protocols must be applicable to national as well as international staff. West African responders worked in large numbers from the early stages of the epidemic right through to its conclusion, and were undoubtedly at the highest risk. We must also ensure that every individual who works in these high-risk settings receives strong support and is thoroughly trained ahead of starting work, including on the use of PPE, how to reduce risk in and out of the red zone, and what to do if they think they have been exposed or if they become unwell."
The authors acknowledge limitations of the study including that not all returning responders were included and participants were not a random sample. It is therefore possible that those who knew of possible exposures, or who had had symptoms, were particularly keen to participate. Since these were the people who were most likely to have been infected, the absence of undiagnosed infections is reassuring.
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Ugonjwa wa Ebola ambao haujagunduliwa ulikuwa nadra sana kwa wafanyakazi wa kimataifa waliotumika wakati wa mlipuko wa virusi vya Ebola huko Afrika Magharibi mnamo 2013-2015, licha ya visa vidogo vya ugonjwa huo ambavyo havikuwa na dalili, kulingana na utafiti mpya uliochapishwa katika jarida la PLOS Medicine. Zaidi ya wafanyakazi 250 wa huduma za afya nchini Uingereza na Ireland walichunguzwa kwa ajili ya antibodies ya virusi vya Ebola baada ya kurudi kutoka Afrika Magharibi, na hakuna ushahidi wa maambukizi yaliyopotezwa. Hii inaonyesha kwamba idadi kubwa ya wajitoleaji walihifadhiwa salama na vifaa vya kinga ya kibinafsi (PPE) na taratibu za kituo cha matibabu ya Ebola. Hata hivyo, utafiti huo pia uligundua kuwa matukio yanayoweza kuepukwa ambayo huweka wafanyakazi wa mstari wa mbele katika hatari ya maambukizi yalikuwa ya kawaida wakati wa mlipuko, na mmoja kati ya washiriki sita waliorodheshwa kuwa na matukio ya 'karibu kukosa' maambukizi. Katika utafiti wa kwanza wa kuenea kwa maambukizi ya Ebola kwa wagonjwa wa kimataifa, timu ya utafiti iliyoongozwa na Shule ya London ya Usafi na Tiba ya Tropiki na kufadhiliwa na Wellcome Trust, ilijiunga na wafanyakazi wa afya wa Uingereza na Ireland 300 na wafanyakazi wengine wa mstari wa mbele kwa utafiti huo na kuwapeleka vifaa vya kukusanya umajimaji wa mdomo. Kati ya wale waliopokea sampuli zao, asilimia 99 walikuwa na matokeo hasi ya mtihani wa kingamwili ambao tayari ulionyesha matokeo sahihi sana nchini Sierra Leone. Watu wawili waliobaki, ambao hawakuwa na dalili za ugonjwa huo, walipata matokeo mazuri, lakini uchunguzi wa kufuatilia kwa kutumia mbinu tofauti ulikuwa hasi, na kufanya maambukizi ya virusi vya Ebola kuwa ya uwezekano mdogo sana.Timu ya utafiti, iliyoongozwa na Shule ya London ya Usafi na Tiba ya Tropiki na kufadhiliwa na Wellcome Trust, ilijiunga na wafanyakazi 300 wa huduma za afya wa Uingereza na Ireland na wafanyakazi wengine wa mstari wa mbele kwa utafiti huo. Kati ya wale waliopokea sampuli zao, asilimia 99 walikuwa na matokeo hasi ya mtihani wa kingamwili ambao tayari ulionyesha matokeo sahihi sana nchini Sierra Leone. Watu wawili waliobaki ambao hawakuwa na dalili za ugonjwa huo walikuwa na matokeo mazuri, lakini uchunguzi uliofanywa kwa kutumia mbinu tofauti ulikuwa na matokeo mabaya, na hivyo kuifanya maambukizi ya virusi vya Ebola kuwa ya uwezekano mdogo. "Mwandishi mkuu wa utafiti huo, Dk Catherine Houlihan, kutoka Chuo cha London cha Usafi na Tiba ya Tropiki na UCL, alisema: ""Mlipuko wa Ebola wa 2013-2015 haukuwa na mfano - kujitolea na ujasiri wa wale waliojitolea kuokoa maisha mengi." """Tunajua idadi ndogo ya wafanyakazi wa afya wa kimataifa waliambukizwa virusi, lakini tulidhani inawezekana kuwa maambukizi fulani yalikuwa yamepuuzwa, kama tunavyojua maambukizi yasiyo na dalili au yasiyojulikana yanaweza kutokea." Hata hivyo, utafiti wetu unaonyesha maambukizi yasiyoonekana katika kundi hili ni, kwa kiwango kikubwa, tukio nadra sana, na kwamba vifaa vya kinga vya kibinafsi vilifanya kazi yao vizuri. Washiriki, ambao ni pamoja na madaktari, wafanyakazi wa maabara na wataalamu wa magonjwa ya kuambukiza, pia walijaza uchunguzi wa mtandaoni ambao uliuliza ikiwa walipata uwezekano wa kuambukizwa virusi vya Ebola wakati wa Afrika Magharibi. Kutumia maelezo ya waliohojiwa 268, 16% (watu 43) walitambuliwa kuwa na matukio ya mfiduo ya 'karibu-kupoteza'. Waandishi wa habari 27 waliripoti kuwa walipata ajali ya hatari ya chini sana, kama vile kuondolewa kwa kinyago cha uso. Katika kesi kumi, watu waliohusika walikuwa na hatari ya chini ya kuambukizwa na mgonjwa wa Ebola ambaye hakuwa na kutapika, kuhara au kutokwa na damu. "Wanafunzi watano walikabiliwa na tukio la hatari ya kati na mmoja wa waliohojiwa aliripoti ""kuchukuliwa wakati wa kuvaa kinga tu"" na sio PPE kamili, na mmoja alipata tukio la hatari ya ""kujeruhiwa kwa makali na vial ya dawa iliyovunjika ndani ya ""eneo nyekundu"" na kinga chafu na chafu." Uchunguzi wa viini vya kinga ulionyesha kwamba hakuna mtu yeyote kati ya watu hao aliyekuwa na dalili za maambukizi ya Ebola. Washiriki waliripoti suti za PPE zilizovunjika kwa kukamata milango au pembe, uvunjaji wa PPE katika maabara ya Ebola, kama vile glavu za nje zilizovunjika, na wasiwasi wa ziada na shida ambazo matukio haya yaliwasababisha. "Catherine Houlihan alisema: ""Ukubwa wa janga hilo ulimaanisha kwamba wafanyakazi wa mstari wa mbele walikabiliwa na hali ngumu na zenye kuchosha." Washiriki wametoa ufahamu muhimu ambao hutoa masomo yenye thamani kwa milipuko ya Ebola ya baadaye. Kujiuliza mara kwa mara baada ya kazi katika eneo nyekundu la kliniki au maabara, na kuripoti bila lawama ya karibu-misses, inapaswa kuwa sehemu ya mazoezi ya kawaida katika kazi ya majibu ya matibabu ya dharura. "Mabadiliko rahisi kama vile kupiga marufuku viwanja vya glasi katika eneo la nyekundu yanaweza kupunguza idadi ya wafanyakazi wanaopata majeraha ya ngozi, na upimaji zaidi wa nguvu na usahihi wa suti za PPE, unaweza kuokoa maisha ya wafanyikazi wa afya katika siku zijazo. """ Washiriki wa utafiti, ambao wengi wao walikuwa Sierra Leone, waliulizwa pia ikiwa walipata homa au kuhara wakati wa safari yao ya Afrika Magharibi au ndani ya mwezi mmoja baada ya kurudi, na ikiwa walikuwa wamejaribiwa virusi vya Ebola wakati huo. "Licha ya dalili katika 21% (5267%) ya waliohojiwa, 70% hawakujaribiwa, na wale ambao bado wako Afrika Magharibi wana uwezekano mdogo wa kupokea mtihani - 11 kati ya 17 waliopata ugonjwa wakati wa kurudi walijaribiwa, lakini mtu mmoja tu kati ya 21 waliopata ugonjwa huko Afrika Magharibi walijaribiwa. """ "Huiliani alisema: ""Utafiti huu hutoa ushahidi wa kuimarisha kuhusu ukosefu wa maambukizi ya Ebola kwa watu ambao hawajawahi kupimwa kwa virusi." Hata hivyo, idadi kubwa ya wafanyakazi wa afya ambao hawakufanyiwa uchunguzi walipokuwa wagonjwa katika Afrika Magharibi, pamoja na uwezekano wa kuambukizwa Ebola kwa wale waliorudi, ni jambo la wasiwasi. Ingawa hatujui ni wafanyakazi wangapi wa afya walioripoti kuwa wagonjwa na walichunguzwa ili kuamua ikiwa wanahitaji kupimwa, itifaki za usimamizi wa uwezekano wa kuambukizwa virusi, na kwa usimamizi wa ugonjwa, zinaweza kuhitaji kukaguliwa na kuwa sawa katika mashirika ambayo hutuma wafanyakazi kwenye milipuko. "Ni muhimu, itifaki hizi lazima zitumike kwa wafanyakazi wa kitaifa na wa kimataifa. "Wajibuji wa Afrika Magharibi walifanya kazi kwa idadi kubwa kutoka hatua za mapema za janga hadi mwisho wake, na bila shaka walikuwa katika hatari kubwa zaidi. """ """Tunapaswa pia kuhakikisha kwamba kila mtu anayefanya kazi katika mazingira haya ya hatari hupokea msaada mkubwa na ana mafunzo kamili kabla ya kuanza kazi, ikiwa ni pamoja na matumizi ya PPE, jinsi ya kupunguza hatari ndani na nje ya eneo la nyekundu, na nini cha kufanya ikiwa wanafikiri wamefunikwa au ikiwa wanakuwa wagonjwa." Watafiti pia wanakubali kuwa utafiti huo ulikuwa na mapungufu, ikiwa ni pamoja na kwamba sio washiriki wote waliorudi walihusishwa na washiriki hawakuwa sampuli ya nasibu. Kwa hiyo inawezekana kwamba wale ambao walijua ya uwezekano wa mfiduo, au ambao walikuwa na dalili, walikuwa hasa nia ya kushiriki. Kwa kuwa hawa ndio watu ambao walikuwa na uwezekano mkubwa wa kuambukizwa, kutokuwepo kwa maambukizi yasiyojulikana ni jambo lenye kutia moyo. Namba hii ya ukurasa: