国产冻干水痘减毒活疫苗免疫原性研究与应用

对１２９名４岁儿童采用国产、进口水痘减毒活疫苗进行免疫,对疫苗的安全性和免疫原性进行研究,用ＥＬＩＳＡ进行免前、免后水痘抗体测定。结果表明国产水痘疫苗接种后无明显副反应,国产、进口疫苗血清的阳转率相似,达８５％以上,证明国产ＯＫａ株水痘减毒活疫苗具有良好的安全性和免疫性,可以推广使用。     

Varicella vaccination: evidence for frequent reactivation of the vaccine strain in healthy children

Wild-type varicella zoster virus (VZV) causes chickenpox, a common childhood illness characterized by fever and a vesicular rash and rare serious complications. Wild-type VZV persists in a latent form in the sensory ganglia, and can re-activate to cause herpes zoster. More than 10 million American children have received the live attenuated Oka strain VZV vaccine (OkaVZV) since its licensure in 1995. Pre-licensure clinical studies showed that mean serum anti-VZV levels among vaccinees continued to increase with time after vaccination. This was attributed to immunologic boosting caused by exposure to wild-type VZV in the community. Here, we examine the alternative, that large-scale asymptomatic reactivation of OkaVZV might occur in vaccinees. We analyzed serum antibody levels and infection rates for 4 years of follow-up in 4,631 children immunized with OkaVZV. Anti-VZV titers decreased over time in high-responder subjects, but rose in vaccinees with low titers. Among subjects with low anti-VZV titers, the frequency of clinical infection and immunological boosting substantially exceeded the 13%-per-year rate of exposure to wild-type varicella. These findings indicate that OkaVZV persisted in vivo and reactivated as serum antibody titers decreased after vaccination. This has salient consequences for individuals immunized with OkaVZV.     

New insights in toxoplasmosis immunology during pregnancy. Perspective for vaccine prevention

Toxoplasma gondii is one of the few pathogens that can cross the placenta. Frequency and severity of transmission vary with gestational age. While acquired toxoplasmosis is already well explored, the control of maternal-foetal transmission of the parasite remains almost unknown. This is partly due to inherent inadequacies of animal models. This review summarises the studies which have been undertaken and shows that the mouse is a valuable model despite obvious differences to the human case. The paramount role of the cellular immune response during primary infection has been consistently shown. Surprisingly, IFN-g has a dual role in this process. While its beneficial effects in the control of toxoplasmosis are well known, it also seems to have transmission-enhancing effects within the placenta and can also directly harm the developing foetus. This shows the importance of designing vaccines which protects both mother and foetus. Therefore, it is useful to study the mechanisms of natural resistance against transmission during a secondary infection. In this setting, the process is more complicated, involving cellular, but also humoral components of the immune system. In summary, even if the whole process is far from being elucidated, important insights have been gained so far which will help us to undertake rational vaccine research.     

Varicella infection in a children's hospital: prevention by vaccine and an episode of airborne transmission

Varicella vaccine was used safely and effectively for preventing ward infection with varicella. Ward infection was experienced 34 times in 5 years between 1977 and 1982. During these ward infections, varicella developed in 4 of 142 patients who received vaccine, 21 of 47 patients who did not receive vaccine and 1 of 9 who received transfusion with vaccine-boostered blood. Of the 142 vaccinated patients, the four in whom varicella developed showed symptoms 3 to 10 days after vaccination, indicating that vaccination had been too late. Details of a ward infection with varicella by airborne transmission and its prevention by vaccination are presented.     

Varicella Pneumonitis

Four adults had varicella pneumonitis. All developed respiratory symptoms within a week of the exanthem. Cough and/or dyspnea, cyanosis and chest pain were common. Radiological signs of disease were more marked than physical signs. A slight polymorphonuclear leukocytosis and normal sputum culture were usual. One man with mild symptoms recovered. Two women, one pregnant, had severe symptoms and died. A second man succumbed to secondary bacterial pneumonia. The lungs in fatal cases showed interstitial pneumonitis with mononuclear cell infiltrate, focal areas of necrosis, and acidophilic inclusion bodies in two cases. Patients received oxygen, antibiotics and, in one instance, corticosteroid therapy. The value of antibiotics and corticosteroid treatment is questionable. Use of gamma globulin in preventing varicella pneumonitis is mentioned and residual pulmonary changes are discussed.     

Varicella morbidity in Czechoslovakia

Data are presented on varicella and herpes zoster morbidity notified in Czechoslovakia in the years 1970 to 1978. The notified varicella incidence is compared with serologically confirmed varicella incidence among the selected groups of children up to the age of 12 from the North-Moravia region. Comparative analysis revealed a considerable difference between the notified and serologically detected cases of varicella. The highest rate of notified varicella was recorded in children of 3 and 4 years of age, while the highest incidence of seropositive cases was detected among the 2-year-old children. The cumulative notified morbidity involved about 35% of 6-year-old and 45% of 12-year-old children, whereas specific antibodies against the varicella-zoster virus were found in about 60% of 6-year-old and 90% of 12-year-old children. The titres of virus-specific antibodies were determined by the method of indirect hemagglutination reaction. No serological methods are applicable for herpes zoster morbidity studies in the population.