Background: Immunization against diphtheria, tetanus and pertussis (DTP) has long been applied in Iran using whole cell vaccine. Despite the role of whole cell DTP (DTwP) vaccine in reduction of mortality as a result of disastrous diseases such as diphtheria, tetanus, and pertussis, serious local and systemic complications have been attributed to these vaccines. This study was performed to determine the complications of DTwP vaccine in infants attending some of the health centers of Tehran in 2006-2007.Methods: In this prospective study, 330 infants were injected with DTwP vaccine manufactured by Razi Institute of Iran.All subjects received DTwP vaccine at 2, 4, and 6 months of age following the national vaccination schedule of Iran. Reactogenicity was assessed by the parents for 7 days post-vaccination using diary cards. Results: Of the 279 infants who completed the vaccination study, pain was the most frequent local reaction after the primary vaccination (68.1-75.3%). The mean diameters of the redness and swelling at first day post-vaccination were 2.81±6.91 and 2.60±7.93 mm in the first dose, 2.40±6.25 and 1.94±5.74 mm in the second dose and 2.24±5.66 and 2.16±6.03 in the third dose, respectively. Fever (axillary temperature >37.5°C) was the most frequently reported systemic reaction during the primary vaccination (53.8-58.8%). All systemic reactions observed after each dose were either reduced or completely disappeared during a week. Conclusion: The high incident of complications observed following vaccination with this cellular triple vaccine may be related to the formulation or the bacterial cell fragments used in vaccine production.

Objective(s): To determine the short-term reactogenicity of diphtheria-tetanus-whole cell pertussis (DTwP) vaccine administered to preschool children in a number of health centers of Tehran in 2006.Methods: In this prospective cohort study, 337 children aged 4-6 years were injected with DTwP vaccine manufactured by Razi Institute of Iran. Reactogenicity was assessed by the parents for 7 days postvaccination using diary cards. Local (pain, redness and swelling) and systemic (fever, loss of appetite, gasterointestinal symptoms, vomiting and eczema) side effects were recorded daily.Results: Out of 337 children, 312 (92.6%) reported local reactions and 220 (65.3%) reported systemic reactions. No serious adverse events related to vaccination were reported. Among local reactions, pain was the most frequent (86.9%), but it was mostly mild or moderate. Redness (52.8%) and swelling (41.2%) were the most frequently observed signs in the second day. The systemic reactions observed in children included fever (48.4%), loss of appetite (24%), gastrointestinal symptoms (5.6%), vomiting (8%) and eczema (2.7%).Only 3.6% of children had auxiliary fever above 39 °C. All signs were observed to have reduced or completely disappeared during a week.Conclusion: Compared with previous reports in Iran, reactogenicity of DTwP of Razi Institute seems to be reduced, but it was still more frequent than the internationally approved cellular vaccine counterparts. Reactogenicity of the cellular triple vaccine may be related to the vaccine formulation or the bacterial cell fragments used in vaccine production.

Liposome-based vaccines represent a significant advancement in immunotherapy due to their versatile ability to encapsulate and present antigens, adjuvants, and targeting ligands. These lipid vesicles, with their biocompatible and adaptable structure, offer enhanced immunogenicity, prolonged antigen exposure, and reduced reactogenicity. By encapsulating therapeutic agents, liposomes protect antigens from degradation and facilitate controlled release, increasing vaccine stability and efficacy. Surface modifications of liposomes enable antigen display strategies that mimic natural immune responses, effectively engaging immune cells. This display, combined with liposome-mediated delivery of adjuvants, amplifies both humoral and cellular immunity by activating dendritic cells, macrophages, T cells, and B cells. Liposomes also allow multivalent vaccine designs, targeting multiple pathogen epitopes, which is crucial for combating complex infections. Advanced techniques, such as covalent conjugation, metal-chelation, and lipid tail anchoring, enhance antigen presentation and immune cell engagement. The size, surface charge, and lipidic structure of liposomes are critical in determining their interaction with immune cells and impact their role as vaccine adjuvant-delivery systems. This review explores the recent innovations in liposome-based vaccines, focusing on mechanisms of antigen presentation, immune activation, and memory formation. The findings underscore the potential of liposomal platforms to serve as a next-generation vaccine technology capable of providing robust and lasting immune responses.