Sayyiduna Abu Hurayra 
reports that Rasulullah
:saw: said,
'There is no such thing as
contagiousness and neither is there (any bad omen in the) month of Safar. (Sahih Bukhari Hadith5707, 5717)
Commentary
There are 2 misconceptions that are removed through this Hadith:
a) The contagiousness of any disease. In this Hadith, Rasulullah
:saw: has refuted its effects, although He
:saw: has advised us not ot mix freely with those who
have major diseases.
The Muhadditheen explain that this is so that in the
event of the second person contracting the disease, his belief will be
corrupted, i.e. instead of attributing it to Allah, he will attribute
its cause to the ‘contagious’ disease.
b) The evil perception that any event which occurs in the month of
Safar (the second month of the lunar calendar) will be a means of bad luck.
Many people postpone their marriage contracts, travel, business deals,
etc. until after the month of Safar. Rasulullah :saw: has rejected this baseless misconception.