A total of 1031 articles were obtained using the electronic strategy search. After removing of 78 duplicate articles, 1453 study were remained for screening. Then, the full‐text of the articles was evaluated and 1289 irrelevant articles were excluded. At the eligibility check stage, 164 articles were examined and 155 of them were omitted. Finally, 9 articles were included in this meta-analysis review, according to PRISMA (Preferred reporting items for systematic review and meta‐analysis) guideline. Figure 1 shows the review process for the included studies.
Accordingly, this Meta-analysis shows the estimation of the influenza prevalence among patients infected with COVID-19 (Table 1). In nine cross sectional studies, the influenza prevalence among patients infected with COVID-19 varied from 0.08 in Nowak study to 49.46% in Simin Ma study. In the present study the clinical characterization among patients infected with COVID-19 and influenza is shown in Table 2.
Co-infection of SARS-COV-2 and influenza
Generally, with the compounding of the results, the influenza prevalence among co-infected patients with the confidence interval of 95 % and with based on random effect model is (I2:95.948%) and it is shown that heterogeneity was observed among the primary results of the studies (Fig 2). Significant statistical heterogeneity based on random effect model are found in the analysis of the influenza (A, B) prevalence among co-infected patients (I2 = 95.977%), and (I2 = 77.350) respectively. The current result is shown that the prevalence of influenza A is higher than influenza B. 2.3(0.5-9.3) vs 0.1 (0.4-3.3). (Figure 3, 4).
Prevalence of clinical characterization and chest radiography among co-infected patients
The forest plot analyses were performed for fever, chest CT abnormalities, diarrhea, fatigue, cough, and difficult breathing.
Fever analysis
Figure 5 (A) shows that most co-infected patients had fever. In the present study, the prevalence of fever is reported in 5 articles comprising 291patients and ranged between 69.56-100%. Combination of these studies in the same manner as for fever, using the fixed effect model revealed that the frequency of fever is (80.6% [95% CI 76.1–84.40, p < 0.153]).
Cough analysis
A total of 5 articles including 124 patients reported on the prevalence of cough, which ranged from 24.83-100%. Due to the heterogeneity in the results of the primary studies, the random-effects model used for assessment. By combining these 6 articles, it is revealed that cough is the second most common symptom presenting in co-infected patients (43.3% [95% CI 24.1–64.8, p = 0.000]). Figure 5 (B).
Fatigue analysis
The prevalence of fatigue is assessed in 5 articles including 37 patients and the rate of fatigue varied between 3.26 and 40%. Based on the homogeneity between the results of the primary studies the fixed effects model was used for assessment. By revealing of articles, the frequency of fatigue in patients is (13.8% [95% CI 5.6–30.3, p =0.000]). Figure 5 (C).
Diarrhea analysis
The prevalence of diarrhea is reported in 4 articles comprising 35 patients and ranged from 3.92–40% respectively. Based on the heterogeneity between the results of the primary studies, the random-effects model was used for assessment. By combining of these articles, diarrhea is determined to have a prevalence of (12.2% [95% CI 3.9–32.3, p = 0.000]). Figure 5 (D).
Difficult breathing analysis
Difficult breathing was less common in the patients of COVID‐19 and influenza. The prevalence of difficult breathing assessed in 4 articles comprising 27 patients and is reported to range from 6.87–100%. Due to the heterogeneity in the results of the primary studies, the random-effects model was employed. Combined analysis of these articles revealed that difficult breathing occurred in (9.3% [95% CI 3.7–21.5, p < 0.010]). Figure 5 (E).
Chest radiography
Among the selected studies, the prevalence of CT abnormalities is reported in 5 articles comprising 272 patients and ranged from 83–100%. By combining the results of these 3 studies, the frequency of CT abnormalities in co-infected patients is (66.8% [95% CI 29.4–90.7, p < 0.001]). As there is heterogeneity between the results for CT abnormalities, the random-effects model was used for assessment. Figure 5 (B).
Table 1: Estimation of the influenza prevalence among patients infected with COVID-19
Influenza B
|
Influenza A
|
Total influenza
|
Number of SARS-CoV-2 patients
|
Language
|
Authors
|
Reference
|
N/A
|
N/A
|
19 (37.25)
|
51
|
English
|
Castillo (2020)
|
(21)
|
23 (7.49)
|
153 (49.83)
|
131 (42.67)
|
307
|
English
|
Yue(2020)
|
(22)
|
1 (0.4)
|
2 (0.8)
|
22 (8.8)
|
250
|
English
|
Ma(2020)
|
(23)
|
N/A
|
1 (0.08)
|
1 (0.08)
|
1204
|
English
|
Nowak(2020)
|
(24)
|
2 (1.73)
|
3 (2.60)
|
5 (4.34)
|
115
|
English
|
Ding(2020)
|
(25)
|
N/A
|
23 (21.90)
|
49 (46.66)
|
105
|
English
|
Hashemi1 (2020)
|
(26)
|
N/A
|
N/A
|
46 (49.46)
|
93
|
English
|
Simin Ma(2020)
|
(27)
|
5 (1.94)
|
2 (0.77)
|
34 (13.22)
|
257
|
English
|
Zhua(2020)
|
(28)
|
0
|
N/A
|
1 (4.16)
|
24
|
English
|
Yanjun(2020)
|
(29)
|
Table 2: Estimation of clinical characterization among patients infected with COVID-19 and influenza.
Chest CT, Abnormalities
|
Difficult breathing
|
Diarrhea
|
Fatigue
|
Cough
|
Fever
|
Number of patients
|
Area
|
Language
|
Authors
|
Reference
|
122 (93.12)
|
9 (6.87)
|
11 (8.39)
|
13 (9.92)
|
40 (30.53)
|
104 (79.38)
|
131
|
Wuhan
|
English
|
Yue(2020)
|
(22)
|
127 (83)
|
11 (7.18)
|
6 (3.92)
|
5 (3.26)
|
38 (24.83)
|
132 (86.27)
|
153
|
Wuhan
|
English
|
Yue(2020)
|
(22)
|
23 (100)
|
2 (8.69)
|
0 (0)
|
3 (13.04)
|
6 (26.08)
|
16 (69.56)
|
23
|
Wuhan
|
English
|
Yue(2020)
|
(22)
|
N/A
|
5 (100)
|
2 (40)
|
2 (40)
|
5 (100)
|
5 (100)
|
5
|
China
|
English
|
Ding(2020)
|
(25)
|
N/A
|
N/A
|
16 (34.78)
|
14 (30.43)
|
35 (76.08)
|
34 (73.91)
|
46
|
China
|
English
|
Simin Ma(2020)
|
(27)
|
272
|
27
|
35
|
37
|
124
|
291
|
358
|
Total of samples
|
|