The syrup has been recognized as “non-potentially dangerous,” which means it does not foster the growth of harmful microorganisms. The directions to refrigerate upon arrival are for quality control, not for safety.
Being out of the fridge for even 4 or 5 days may shorten its complete shelf life of 60 days but will not compromise the safety of the product. The Elderberry syrup recommends keeping it in the fridge as soon as it arrives!