When a long rest is required due to the flu, many people struggle with the decision: “Should I use my valuable paid annual leave, or should I take the Sickness and Injury Allowance (Shoˉbyoˉ Teate-kin) for 2/3 of my salary?” If both could be used together, the financial anxiety would be greatly alleviated.
The conclusion is that while you absolutely cannot stack both benefits on the same day, it is possible to “combine” them by adjusting the timing or switching the paid leave retroactively.
Paid Leave and Sickness and Injury Allowance “Can It Be Combined?” The Complete 2025 Rules Chart
| Situation | Paid Leave Used? | Sickness and Injury Allowance Paid? | Conclusion (As of 2025) |
| Using Paid Leave First | Yes (e.g., 3 days of paid leave) | Yes, but only for the subsequent days (from the 4th day onward). | ◎ Combination OK (Used sequentially). |
| Stacking Paid Leave and Allowance on the Same Day | Yes | No | × Absolutely Forbidden(Double-dipping is prohibited). |
| Switching Paid Leave Retroactively to Allowance | Yes → No (After switching) | Yes (After switching) | ◎ YES! (Super important technique). |
| Company mandates “Use Paid Leave before Allowance” | Yes | Yes | ◎ Legal (Common pattern). |
| Part-time/Arubaito (No Paid Leave) | No | Yes | 100% Sickness and Injury Allowance. |
2025 “Best Way to Receive Payment” Ranking
| Rank | Method | Amount Received | Recommendation |
| 1st | Use all Paid Leave, then Sickness and Injury Allowance. | 100% initially → then 2/3. | ★★★★★ (Zero loss). |
| 2nd | Switch Paid Leave retroactively to Sickness and Injury Allowance. | Past paid leave days are returned, switched to 2/3 →Receive the 1/3 difference as an additional payment. | ★★★★★ (Ultimate technique). |
| 3rd | Use Sickness and Injury Allowance only from the start. | 2/3 for the entire period. | ★★★☆☆ (Preserves Paid Leave balance). |
How to Switch “Paid Leave → Sickness and Injury Allowance” to Recover the Difference (Possible in 2025)
- Rest for 7 days due to the flu.
- Initially use 7 days of Paid Leave to receive 100% of your salary.
- After returning, request the company to “change the Paid Leave retroactively to Sickness and Injury Allowance.”
- The company returns the 7 days of Paid Leave to your balance. The Health Insurance Fund then pays you the Allowance (2/3) for those 7 days.
- Result: You received 100% from the company (Paid Leave) + 2/3 from Health Insurance (Allowance). Since the Allowance and Paid Leave cannot stack, the Allowance payment is considered a top-up. You essentially keep the 100% paid salary and the Allowance covers the 1/3 difference between 100% and 2/3 for those days.
→ Result: 100% salary + 1/3 bonus (Effectively 133% received).
Note: This is generally OK with Kyōkai Kenpo and most Health Insurance Associations in 2025 (Application required).
Summary
“Combining is OK as long as they are not stacked on the same day.” → Use Paid Leave completely first, then the Sickness and Injury Allowance. → Or, retroactively switch to the Allowance to receive the additional 1/3 difference—this is the strongest method!
It is now a time where you can receive 100% salary + α even if you miss 7 days of work due to the flu!
At-Home Testing Kit Ranking (Combined COVID-19 and Influenza)
Here is the English translation of the ranking table for at-home diagnostic kits that test for both COVID-19 and Influenza A/B:
| Rank | Product Name (Manufacturer) | Targets Detected | Sensitivity (Detection Rate) (Estimate: 12-48h Post-Onset) | Result Time | Approximate Price (Per Test) | Suitability for Pregnant Women / Children | Key Features & Availability |
| 1 | Panbio COVID-19/Flu A&B | COVID + Flu A/B | COVID: Approx. 90% | Flu: Approx. 85% | 15 mins | ¥1,980 – ¥2,480 | ◎ (Shallow Nasal Swab) |
| 2 | クイックナビ-Flu+COVID | Same (COVID + Flu A/B) | COVID: 88% | Flu: 80–85% | 15–20 mins | ¥1,780 – ¥2,200 | ◎ (Designed for children’s use) |
| 3 | KBMラインチェック nCoV/Flu | Same (COVID + Flu A/B) | COVID: 85% | Flu: Approx. 80% | 15 mins | ¥1,480 – ¥1,980 | ◎ |
| 4 | イージードック Flu＆COVID-19 | Same (COVID + Flu A/B) | COVID: 87% | Flu: 82% | 15 mins | ¥2,200 – ¥2,600 | ◎ (Many cases of use by pregnant women) |
