Adverse events after polysaccharide meningococcal A&C vaccine

Safety data on meningococcal polysaccharide vaccine from the Vaccine Adverse Event Reporting System

Recent recommendations by the Centers for Disease Control and Prevention's Advisory Committee on Immunization Practices may lead to the increased use of the meningococcal polysaccharide vaccine. The Vaccine Adverse Event Reporting System (VAERS) is useful for the detection of previously unrecognized reactions and for the monitoring of known reactions. Limitations of VAERS include underreporting and the inability to establish a causal relationship between vaccination and adverse events in most cases. From July 1990 through 31 October 1999, 110 adverse events were reported after receipt of meningococcal vaccine alone. Thirteen (12%) were serious, including 6 injection site reactions, 3 allergic reactions, 1 case of Guillain-Barré syndrome, and 3 miscellaneous events. Fever (30%), headache (17%), dizziness (15%), injection site hypersensitivity (13%), urticaria (12%), and paresthesia (10%) were among the most common events reported. Fever and injection site and allergic reactions are most likely causally linked to the vaccine. That there were few reports of serious adverse events, with >6 million doses having been distributed, and no clear signal of a previously unrecognized serious reaction is reassuring with regard to the safety of meningococcal vaccine.

[Research activity on pediatric vaccines in Spain: descriptive analysis of prospective studies published between 1990 and 1998]

OBJECTIVE

To describe the overall characteristics of prospective studies on vaccines in children, performed by Spanish investigators and published between 1990 and 1998.

METHODS

Through a bibliographic research on MEDLINE and EMBASE, 24 prospective studies, performed in Spain, published as original papers, and with objectives directly related to the administration of vaccines to children have been identified. These studies were grouped as: clinical trials (group A), studies performed on established vaccination programmes (group B), and those that could not be included in the above mentioned groups (group C).

RESULTS

5, 9 and 10 studies belonged to groups A, B and C, respectively. More than 12,800 subjects participated in these studies, belonging to both normal population or specific risk groups. In 11 studies, the study population comprised newborns and infants. The vaccines under investigation were: hepatitis B (10 studies), DTPe/Pa (6), MMR (3), flu (2), Hib (1), hepatitis A (1), and meningococcus A and C (1) to address different objectives (in most of them, immunogenicity and/or reactogenicity). Nine had external financial support; 21 were performed by hospital and/or primary care investigators, and 18 in the Vasque Coutry, Madrid or Valencia. 13 publications reported obtaining informed consent, and 8 on the approval of the study protocol by an independent committee. Ten studies were published by international journals.

CONCLUSIONS

This study shows that most of the studies are conducted by clinicians, with vaccines targetted to newborns and infants, with no external financial support, in a small number of autonomous communities, and usually published in Spanish Journals. The submission of this type of studies to a research ethics committee is desirable, something done to a lesser extent than obtaining informed consent.