Table 2. Case fatality ratio (CFR), Effective Reproduction Numbers and related hypotheses from Nipah spillovers/outbreaks in Kerala (Both RTPCR confirmed and probable cases were included in the table unless specified otherwise) [1, 2, 6–8, 71, 85].
| Attribute | Frequency* | Percentage (%)/ Mean (Range)* | Hypothesis* | Risk of bias* |
|---|---|---|---|---|
| CFR among primary cases | 5/6 | 83.33% | Case fatality is more in primary cases | The difference is narrow, statistically not significant (Fisher exact test). There may be a delay or absence in diagnosis and starting treatment for a primary case |
| CFR among RTPCR confirmed primary cases | 4/5 | 80.00% | ||
| CFR among secondary/tertiary cases | 21/27 | 77·80% | ||
| CFR among RTPCR confirmed secondary/tertiary cases | 17/23 | 73·90% | ||
| CFR among patients who did not receive any anti-viral medication | 14/14 | 100.00% | Case fatality among patients receiving anti-viral medication on a compassionate ground is low (statistically significant difference, Fisher exact test p value = 0.013). The findings is in agreement with other contexts with Clade I infection. | There may be a selection bias. Patients with comparatively a milder disease with slow progression may get treated with antiviral drugs |
| CFR among patients received some anti-viral treatment | 12/19 | 63.16% | ||
| CFR among patients received Ribavirin | 6/11 | 54.54% | ||
| CFR among patients received Remdesivir | 0/3 | 0.0% | ||
| Reproduction number of primary cases | 25/6 | 4.17 (0–20) | Reproduction number of primary cases is high. So the chance of superspreading is high with the primary case. The findings is in agreement with other contexts with Clade I infection. | |
| Reproduction number of secondary cases | 2/25 | 0·08 (0–1) | There may be a selection bias because the secondary and tertiary cases might have identified and isolated early. | |
| Reproduction number of tertiary cases | 0/2 | 0.00% | ||
| Reproduction number of primary cases not isolated before the start of respiratory symptoms | 27/2 | 13·50 (0–22) | Reproduction number of primary cases not isolated before the start of respiratory symptoms is high. So the chance of superspreading is high with those case | NA |
| Reproduction number of primary cases isolated before the start of respiratory symptoms | 0/4 | 0.00 |
*Studies given as references are the sources of data used in this table