Expected Reactions That Are Not Adverse Events

Not all reactions that occur during the vaccination sequence are unexpected and/or characterized as adverse events. Some reactions are expected in normal individuals and require no specific treatment. Symptomatic therapy and reassurance suffice.

Normal Systemic Symptoms
At about one week post-vaccination, one expects to see systemic symptoms in many vaccinees. Fever, malaise, soreness at the vaccination site, myalgia, local lymphadenopathy, and intense erythema ringing the vaccination site can be expected. 

Normal Local Reactions
Normal local reactions that are not considered adverse events can include:

For further information and photographs of normal and variants of normal reactions, please see the General section and Normal Variants section of the Normal Reactions page. For information on revaccination reactions, please visit the Revaccination section of the Normal Reactions page.

Differentiating Cellulitis and Lymphangitis from Bacterial Infection
Viral cellulitis and lymphangitis/lymphadenitis due to vaccinia must be differentiated from bacterial infection of the site. In bacteria superinfection, the vaccination site has either vesicles and pus (staphylococcal infections) or a heaped up eschar characteristic of Group A Beta-hemolytic streptococcal infections. Infection with anaerobic or enteric bacteria may be more difficult to distinguish since both produce local tissue necrosis and can resemble a severe normal vaccination reaction. Cultures of the site may help to distinguish bacterial from vaccinia infection.