What Employers and Employees Need to Know 

As winter sets in, employers face two challenges: a severe flu season and the usual spike in sickness absences over the festive period. Both can disrupt operations, so proactive planning is essential to protect staff, maintain business continuity, and comply with legal obligations. 

Under UK law, employers have a duty to ensure, as far as reasonably practicable, the health, safety, and welfare of employees. This includes mitigating risks from seasonal illnesses like flu. Risk assessments should be reviewed to address flu-related hazards, and organisations should reinforce their health and safety policies, making clear how these apply during periods of increased illness. 

While employers cannot mandate flu vaccination, they can encourage uptake and make access easier. Promoting the NHS flu jab programme, sharing information about eligibility and benefits, and offering workplace flu clinics or flexible time off for appointments are effective strategies. Well-informed employees are more likely to make health-conscious decisions, which benefits both individual wellbeing and organisational resilience. 

Employers should revisit and communicate sickness policies to reassure staff and reduce infection spread. Clear reporting procedures, discouraging presenteeism, and offering flexible work arrangements such as remote or hybrid options can help maintain continuity while limiting contagion. Supporting employees through high sickness periods demonstrates a commitment to wellbeing and helps sustain morale. 

Increasing cleaning of high-touch areas, providing soap, sanitiser, and tissues, and encouraging good etiquette such as covering coughs and sneezes can significantly reduce transmission. Optional mask use for symptomatic staff, as recommended by health leaders, may also help curb infection in close-contact settings. 

Employers should pay particular attention to vulnerable employees, including those with chronic conditions, pregnancy, or compromised immunity. Reasonable adjustments under the Equality Act 2010 may include remote work, adjusted duties, or enhanced PPE. Tailored measures reduce health risks and ensure compliance with equality obligations. 

Which brings us to the issue with absences itself. UK employment law and ACAS guidance make clear that employees are entitled to take time off when they are genuinely unwell, even during public holidays and employers must treat these absences fairly and consistently. According to ACAS, if an employee falls ill during holiday or a public holiday, the period should be treated as sick leave, with entitlement to statutory sick pay (SSP) and accrual of holiday entitlement, provided the employee reports their sickness as soon as possible.  

For absences of seven calendar days or less, including bank holidays, employers can rely on self-certification, a simple confirmation from the employee on return to work. Employers cannot demand a fit note for such short absences. However, for absences exceeding seven days, including weekends and public holidays, employees must provide a fit note. Employers are legally entitled to request this once the seven-day threshold is passed, and may require it before SSP or company sick pay continues. Some employment contracts or staff handbooks can include clauses allowing employers to request fit notes for absences immediately before or after public holidays, such requests are permissible only if explicitly stated in writing and consistently applied across the workforce.  

Employers should therefore review their contractual documents and policies to confirm what provisions exist around requiring fit notes, particularly during the festive window when patterns of absence might raise concern. Imposing additional requirements such as a fit note starting day one or selectively targeting festive sick leave, could breach contract terms or be deemed unfair or discriminatory if not clearly stated. 

Recording and tracking festive sick leave is also key. Employers should ensure staff report their absence promptly, per usual sickness policy, and line managers should conduct return-to-work discussions to confirm self-certifications and explore any welfare issues. These conversations are crucial during holiday periods when mental‑health factors such as stress, travel disruption, or isolation might contribute to absence. 

It’s equally important to avoid troubling patterns that could lead to differential treatment or indirect discrimination, for example, treating individuals with caring responsibilities more harshly. A fair, consistent approach protects the company legally and fosters trust with employees, especially during the holiday backdrop. 

If an employee falls ill while on annual leave, they may be entitled to treat those days as sick leave rather than holiday, provided they follow the organisation’s sickness reporting procedures. Entitlement depends on working time legislation and contractual provisions. Please take advice on this from our Legal and HR team, as this may mean they can reclaim the annual leave for future use. Employers should ensure their policies clearly state that employees must notify the company promptly and provide evidence (such as a fit note) if the sickness lasts more than seven calendar days, including weekends and public holidays. Some contracts include clauses requiring a doctor’s certificate for sickness immediately before or after holiday periods; these are enforceable only if clearly written and applied consistently. Employers should check their contractual provisions and communicate expectations to avoid disputes and ensure compliance. 

This winter brings unique challenges for employers, from managing flu-related risks to handling festive-period absences fairly. The key is preparation: review health and safety measures, promote prevention, and ensure sickness policies are clear and legally compliant. Treat employees consistently, respect their rights under UK law, and avoid knee-jerk reactions that could lead to disputes or discrimination. By combining proactive health measures with fair absence management, employers can protect their workforce, maintain morale, and keep operations running smoothly throughout the season.