Assessment of Active Case Search of COVID-19 in Healthcare Facilities during the Third Wave of the Pandemic in Ekiti State, Nigeria

Early case detection and isolation of patients infected with highly infectious diseases through active case search (ACS) are important for early commencement of treatment and control of the disease within a population. This study aimed to assess the ACS of COVID-19 in healthcare facilities during the third wave of the pandemic in Ekiti State, Nigeria. This cross-sectional study was conducted in all healthcare facilities in Ekiti State. All cadres of local government primary healthcare workers were trained to carry out the ACS using semi-structured interviewer-administered questionnaire uploaded on android phone software open data kit (ODK). ACS was conducted between June and September (epidemiological week 23 to 36), 2021 and the collected data were analyzed using IBM SPSS version 23.0. P-value < 0.05 was taken as significant. The number of ACS visits for COVID-19 increases with epidemiological week progression, but the highest was in week 32 (9.9%). Cases of suspected COVID-19 in the healthcare facilities in the last one week were reported in more than half (58%) of the visits and 57.8% of those reported, documented between 1 - 4 cases. Also, out of those that were reported, 42% of them missed (not line listed) at least one suspected case of COVID-19. The private health facilities missed more cases of COVID-19 (54.3%)


Introduction
Corona virus disease  is an infectious disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) [1]. The first confirmed case of the disease was discovered in Nigeria on 27th February 2020 by Nigeria Center for Disease Control (NCDC), [2] following this, 208,630 cases have been confirmed with 2767 deaths as of 15th October 2021. [3] The advent of the delta variant of SARS-CoV-2 poses a great deal of problem in Nigeria and other affected countries. The delta variant is recognized by the World Health Organization (WHO) as a variant of concern, given its increased transmissibility. The variant has been detected in over 90 countries and is expected to spread to more countries. The variant has also been linked to a surge in cases in nations where it is the dominant strain in circulation and it has been implicated in the third wave of COVID-19 disease [4].
Active case search (ACS) is a systematic search for symptomatic cases of an infectious disease using a specified case definition and has been used in infectious diseases such as poliomyelitis; its use in COVID-19 pandemic third wave has not been well documented [1]. ACS is an important approach for capturing all the cases, as many may not have access to healthcare facilities and may seek care elsewhere during outbreaks of disease especially in pandemic season of COVID-19 [5] [6]. Early case detection and isolation of patients infected with highly infectious diseases are important for early commencement of supportive treatment and control of further transmission of the disease within a population [1] [7] [8].
ACS is a key surveillance activity for control of epidemic prone diseases such as COVID-19, which relies on active early identification of suspected cases which may not otherwise be reported [9] [10]. ACS teams may visit households or health facilities to look for possible COVID-19 cases [11]. Health facilities provide an appealing location for ACS based on symptoms screening. Due to the severity of symptoms individuals with COVID-19 are likely to come in contact with the healthcare system during the course of their illness. These cases may however not be reported due to lack of awareness of signs and symptoms of COVID-19 and the procedure for reporting suspected cases [12].
The COVID-19 virus is rapidly evolving [13] and such evolution requires continuous watch and scrutiny at all levels. A robust comprehensive surveillance, once in place, should be maintained even in areas where transmission has been suppressed or controlled, even if there are few or no cases. However, given the time required for adequate immunization coverage in the population at large, subsequent pandemic waves are anticipated and detection methods for SARS-CoV-2

Methodology
This study is a cross-sectional study carried out between June (Epidemiological Clinical criteria: Acute onset of any two or more of the following signs or symptoms: fever, cough, runny nose, sore throat/pharyngitis, headache, difficulty breathing/dyspnea, nausea, loss of taste, loss of smell, general weakness/fatigue, diarrhea, chest pain, vomiting, chills/sweating, muscle pain/myalgia, wheezing, abdominal pain, altered mental status. Option C: A person not meeting epidemiological criteria with a positive SARS-CoV-2 antigen-detecting rapid diagnostic test (Ag-RDT), irrespective of any symptoms.
Option D: Close contact of a confirmed case, irrespective of any symptoms.
Anyone of the four options A to D qualifies as a suspected COVID-19 case. Using this case definition of suspected COVID-19 case, the trained local government healthcare workers reviewed all medical records within the last one week in the health facilities. Symptoms and signs of COVID-19 from the suspected case definition were then assessed whether to validate these as suspected COVID-19 case based on the clinical features and epidemiological link of the patient. The team also assessed healthcare facilities workers knowledge of suspected case definition of COVID-19 and the process for notifying. Upon visit to the health facilities, the trained local government healthcare workers presented themselves to the officer in charge (OIC) of the health facilities to discuss their visit and to request designated focal points where medical records would be reviewed and ACS could be carried out. These trained local government healthcare workers started by asking questions on signs and symptoms of COVID-19, if anyone has presented within the last week with such feature, they also go through the out-patient register of the health facilities to see if there is any case that meets the suspected case definition of COVID-19 in the last one week. Cases that meet the suspected case definition were then contacted and confirmatory tests carried out. Confirmed cases were then treated as per protocol based on severity of symptoms.
Semi-structured interviewer-administered questionnaire uploaded on android phone software open data kit (ODK) was used to collect information at the health facilities. Data collected by the trained local government healthcare workers included: the epidemiology week of the visit, health facility type, knowledge of the suspected case definition by the healthcare workers in the health facilities, cases of suspected COVID-19 seen in the healthcare facilities in last one week and cases of suspected COVID-19 missed (not line listed) in the healthcare facilities in last one week. The WHO epidemiological week calendar was used to determine the week based on the date of the visit. Health facilities were categorized based on type into public primary, public secondary, public tertiary and private health facilities. Collected data were downloaded from the ODK and analyzed using IBM SPSS version 23.0. Frequency and percentages were presented in tables at univariate level of analysis. Chi-square was used to assess the association between ACS and independent variables. P-value < 0.05 was taken as significant.

Active Case Search Conducted by Epidemiological Week, Designation and Health Facility Type
A total of 2640 ACS were conducted within the fourteen (14)  Majority (87.2%) of the ACS were carried out at the primary health facilities, followed by secondary health facilities with 7.7% of cases. The private health facilities accounted for 4.5% of the cases while the tertiary health facilities contributed only 0.6% of the COVID-19 ACS (Table 1).

Active Case Search
Cases of suspected COVID-19 in the healthcare facilities in last one week were reported in more than half (58%) of the visits and 57.8% of those reported, documented between 1 -4 cases. Also, out of those that were reported, 42% of them missed (not line listed) at least one suspected case of COVID-19. Majority (98.5%) of the health care workers know about the standard case definition of COVID-19 as against only 1.5% of them who don't know the disease case definition ( Table 2).

Relationship between Designation of Healthcare Workers and Active Case Search
The laboratory scientist had the least number of missed cases (29.9%) out of the cases searched by them while the health educators and LIO found most missed

Discussion
The overall case search during 14-week period of the epidemiological week was 2640 cases. This number increases with progression in the week except for a minimal reduction towards the last 3 weeks. The steady increase earlier seen might be due to the increase in awareness on ACS of COVID-19 as the week progresses while the late reduction seen may be due to reduced COVID-19 cases as well as fatigue by the healthcare workers. This progressive increase is comparable with the weekly increase in incidence of COVID-19 in Africa continent during the fourth wave of the disease [17]. prehensive ACS which will involve search in both the health facility and the community.
In conclusion, the number of ACS increases with progression in the epidemiological week but efforts must be put in place for sustenance of this progress to avoid waning off seen towards the tail end of the weeks. Also, the private health facilities with lower knowledge of the standard case definition had a higher proportion of missed cases of the disease, this may suggest that better knowledge and understanding of the standard case definition may help detection of more suspected cases and reduce missed cases. Lastly, the health educator and LIO detected the highest proportion of missed suspected cases which shows that disease surveillance officers alone may not be adequate to conduct ACS, other LGA teams should be carried along and actively involved.