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ABC triage and Protect phase strategy in COVID-19 management: lessons from the past
  1. Pranav Ish1,
  2. Pirabu Sakthivel2,
  3. Nitesh Gupta1,
  4. Nipun Malhotra1,
  5. Madhu Rajeshwari3
  1. 1 Department of Pulmonary, Critical Care and Sleep Medicine, Vardhman Mahavir Medical College and Safdarjung Hospital, New Delhi, India
  2. 2 Head and Neck Surgery & Oncology, All India Institute of Medical Sciences, New Delhi, India
  3. 3 Pathology, All India Institute of Medical Sciences, New Delhi, India
  1. Correspondence to Pirabu Sakthivel, Department of Otorhinolaryngology and Head-Neck Surgery, All India Institute of Medical Sciences, Teaching Block, New Delhi 110029, India; pirabusakthivel{at}

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Dear Editor,

Pandemics by their nature are unpredictable and the COVID-19 pandemic came about a decade after the H1N1 pandemic in 2009. However, the lessons learnt from the previous outbreak should not be forgotten. Over a 2-month period in 2009, the Ministry of Health and Family Welfare in India reported over 40 000 infected people and resulting in over 2000 deaths [mortality rate—6%] attributable to H1N1.1 Resource limited countries like India with already overburdened healthcare services were hit hard with large numbers of H1N1 patients, and eventually devised a practical strategy of clinical categorisation into A, B and C groups (figure 1). This categorisation was a tool for simple yet uniform triage that resulted in judicious use of testing kits, hospital personnel and admission facilities.

Figure 1

H1N1 influenza management according to severity assessment.

COVID-19 has already spread to the entire world to over 200 countries. India has nearly six million diagnosed cases with over ninety thousand deaths until 26 September 2020 [mortality rate—2%].2 This is a lower mortality rate when compared with H1N1, but with a higher incidence. The WHO in its latest document has classified COVID-19 into mild, moderate, severe and critical disease.3 The definitions are easy to follow and usually need a pulse oximeter only to classify as moderate (pneumonia with spO2 >90%) and severe (spO2 <90%). The guidelines suggest management of mild and moderate cases at home, community facility or health facility. Though international collaboration remains a critical component to respond effectively to pandemics in the current globalised world, there is an unmet need to develop each country’s own treatment policies.


As the initial reported literature from India has also reported mild cases with spontaneous recovery from various tertiary care centres, such patients can be managed with home isolation, thus sparing hospital admission services for sicker patients.4 With limited healthcare infrastructure facilities and with 1.3 billion population following a similar triage with home care for mild and moderate cases is of paramount importance. A suggested classification criterion taking cues from H1N1 influenza and WHO categories of COVID-19 can include A, B and C groups (figure 2). Group A can cover mild cases of fever, myalgia, cough and sore throat along with the asymptomatic and pre-symptomatic cases. These patients must remain in contact with surveillance officers and home-isolated with symptomatic treatment. B group can be again split into B 1 and B 2 . B 1 will include fever with pneumonia (on radiology) with preserved oxygen saturation. Such patients should be managed with home-isolation with frequent surveillance and regular pulse oximeter. B 2 will include B 1 with comorbidities, extreme age groups and immunocompromised which should be cared for at primary care hospitals. Group C can be reserved for those having hypoxia, hypotension, cyanosis, tachycardia, tachypnoea, sepsis or septic shock. These patients essentially require care in high dependency units or intensive care units or wards with ventilatory facility available at community health or tertiary care centres. These hospitals should be earmarked for COVID-19 patients with dedicated staff and isolation facilities. Other non-pulmonary manifestations can also be included in this group until further studies are available on their prevalence and treatment.

Figure 2

Suggested similar ‘ABC’ triage COVID-19 management according to severity assessment taking cues from H1N1 management.


The strategy to categorise patients on the basis of severity of illness is an essential step towards ensuring that in-hospital and critical care are available to those who need it the most, the basic principle of epidemic management, that is, ‘appropriate utilisation of resources’. Mass population strategies lead to misuse of large amounts of scarce medical resources which continue to dwindle in India. Australia in 2009 during the H1N1 pandemic, employed a new ‘Protect phase’ strategy when initial attempts at containment were unsuccessful focussing health resources on those who were known to be at a higher risk and thus more vulnerable to complications rather than the entire population.5

The Kerala state government had adopted a similar ABC triage system since the beginning of the epidemic in India and has been managing COVID-19 successfully and recently awarded the United Nations award for its ‘outstanding contribution’ towards the diseases-related sustainable development goals.6 Another study from India has tried to study the use of a double triage system with stress on vigorous screening.7 This is crucial during an outbreak where hospitals can be quickly overwhelmed if hospital care is given on a first-come-first-serve basis rather than triage-based scrutiny.


There is always an undue focus on medical interventions such as drugs and vaccines during a pandemic. We need to learn the lessons from the past. The similarities between H1N1 and COVID-19 (table 1) should prompt us to use the understanding and successful management strategy of one disease for the other emerging as a pandemic.

Table 1

Features and key similarities between influenza A (2009 H1N1) and COVID-19

Widespread use of masks, alcohol hand hygiene, contact tracing, social distancing and early quarantine of cases is the key to effective management of COVID-19. As containment is unlikely and also no availability of vaccines in a timely fashion, effective ABC triaging and Protect phase implementation across the country is obligatory to battle this pandemic. Recovery from this pandemic will be a long haul, and only those who brace for change will thrive. As uncertainty is ingrained in COVID-19 pandemic we need global health experts to be open about the ‘knowns’, ‘known unknowns’ and ‘unknown unknowns’, after which government officials and policy makers need to provide appropriate solutions.



  • Contributors PI, PS and NG—design & drafting of manuscript and acquisition of information. PS, NM and MR—editing, literature review and critical revisions. All authors read and approved the final version of the article.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Patient consent for publication Not required.

  • Provenance and peer review Not commissioned; internally peer reviewed.