Western work conditions take it as a given that employees are paid for many days for which they do not actually work. Vacation time, sick days, maternity leave, personal time are all part and parcel of standard work conditions. These employee benefits are of relatively recent vintage and find no basis in Jewish law, other than minhag hamakom (local custom), that in establishing work conditions, local practice, not to mention civil law, is binding on all even if it contravenes theoretical Jewish law. In Talmudic times most workers were hired for the day. The notion of an indefinite hire so common today did not exist; thus the concept of employee benefits had no relevance.
Remuneration, Judaism understood, was to be given only for work actually performed. To do otherwise would be to unfairly penalize employers. While it may be no fault of the employee that they are sick, it is not the responsibility of the employer either. In the unfortunate situation where the sick employee is in economic straits it is society as a whole, i.e. government benefits, not just the unlucky employer that would have to supply the charitable funds needed to sustain a person through his illness.
Only in cases where information is improperly withheld could an employee claim pay for work not actually performed. Thus for example if one hires a tour guide prior to a planned trip to Israel but neglects to mention that work pressures often lead to last minute cancellations, the guide can rightfully expect payment, albeit of a reduced amount. Recognizing that most workers would willingly stay home if they could receive a substantial amount of their wages, this reduced amount is determined by calculating that amount. Modern day authorities assume that for most workers it is 50% which interestingly enough is the percentage the Canadian government pays as (un)employment insurance. Of course if that trip is cancelled for unforeseen circumstances i.e. illness in the family then the tour guide is out of luck.
Being sick does have halachic (legal) ramifications in at least two areas. In order that employees not have a feeling of servitude, Jewish law grants the worker the right to quit at any time, with no notice. This right however is suspended in cases where quitting would cause an immediate and unrecoverable loss - for example a farm worker quitting just as the crops are to be harvested or a band leader resigning the night before a wedding - and in such situations reasonable notice, i.e. time to find a replacement worker, must be given. Quitting without the appropriate notice may make one liable for financial penalties over and above lost wages. However this restriction and possible fine is waived in the case of illness not just for the employee but also for the illness of his wife and/or children. While the employee can not expect remuneration for time ill neither can he be held responsible for employee losses due to illness.
There are however a particular groups of workers who are entitled to full pay for time off due to illness. As Jewish law forbids the taking of money for performing a mitzvah the payment of salaries to those whose work are intrinsic mitzvoth such as teachers and health care professionals are based on sechar batala, loosely translated as opportunity cost. In essence they are paid for not taking a job in another more neutral field, and they then agree to work for "free" in caring out their mitzvah duties. As they are not actually being paid for their actual work salary would not be deducted in the case where they legitimately missed "work".