Gabriel Wolf Oselka

Importance of background rates of disease in assessment of vaccine safety during mass immunisation with pandemic H1N1 influenza vaccines.

Because of the advent of a new influenza A H1N1 strain, many countries have begun mass immunisation programmes. Awareness of the background rates of possible adverse events will be a crucial part of assessment of possible vaccine safety concerns and will help to separate legitimate safety concerns from events that are temporally associated with but not caused by vaccination. We identified background rates of selected medical events for several countries. Rates of disease events varied by age, sex, method of ascertainment, and geography. Highly visible health conditions, such as Guillain-Barré syndrome, spontaneous abortion, or even death, will occur in coincident temporal association with novel influenza vaccination. On the basis of the reviewed data, if a cohort of 10 million individuals was vaccinated in the UK, 21.5 cases of Guillain-Barré syndrome and 5.75 cases of sudden death would be expected to occur within 6 weeks of vaccination as coincident background cases. In female vaccinees in the USA, 86.3 cases of optic neuritis per 10 million population would be expected within 6 weeks of vaccination. 397 per 1 million vaccinated pregnant women would be predicted to have a spontaneous abortion within 1 day of vaccination.

Recommendations are needed for adolescent and adult pertussis immunisation: rationale and strategies for consideration

Pertussis vaccination of infants has dramatically reduced disease, complications and deaths in infancy and early childhood. But there is still a major public health challenge--to deal with the morbidity and economic burden of illness in older children, adolescents and adults. Furthermore, it is these groups that form a major source of infection for non-immunised and partially immunised infants who are at high risk of severe complications. Adult-type acellular pertussis vaccine confers safe and effective protection against pertussis. There are several strategies to consider for immunising older individuals. Universal vaccination of all age groups would be the best available strategy for protecting individuals. It would also reduce the potential for transmitting the disease to other susceptibles, particularly infants. However, such a policy may be difficult both logistically and economically at this time. More easily achievable as a first step would be a strategy of universal adolescent booster vaccination combined with a programme targeted at adults most likely to have contact with very young babies including healthcare and childcare workers, parents and close family contacts. There is also potential for offering vaccination to adults (and their carers and close contacts) whose medical conditions or advanced age may place them at increased risk of more severe pertussis disease. Specific details of immunisation programmes must be made on a country by country basis depending on local circumstances.

Recent immunization against measles does not interfere with the sero-response to yellow fever vaccine

In order to determine whether previous measles vaccination interferes with the sero-response to yellow fever vaccine, 294 children at nine months of age were randomly assigned to immunization with yellow fever vaccine at different time intervals after measles vaccination. The seroconversion rate (SCR) and the log10 geometric mean titer (GMT) for 17 DD yellow fever vaccine at different intervals after Schwarz measles vaccination were: 1-6 days: SCR = 44/57 = 77%; GMT = 4.57; 7-13 days: SCR = 36/53 = 68%; GMT = 4.46; 14-21 days: SCR = 55/65 = 85%; GMT = 4.46; 22-27 days: SCR = 41/54 = 76%; GMT = 4.41 and >28 days: SCR = 52/65 = 80%; GMT = 4.24 (p > 0.05). We conclude that recent immunization against measles does not interfere with the sero-response to yellow fever vaccine.

Visceral leishmaniasis: clinical and laboratorial aspects

OBJECTIVE To compare the clinical and laboratorial data before and after the treatment of patients with visceral leishmaniasis admitted to a pediatric hospital in a nonendemic area, highlighting the importance of recognizing visceral leishmaniasis in pediatric patients. METHODS Clinical, laboratorial and treatment data of 78 patients with visceral leishmaniasis were evaluated from 1981 to 1992. We analyzed the average level of hemoglobin, leukocyte, neutrophil, platelet, albumin, gammaglobulin, class and subclass of immunoglobulin, size of the liver and spleen during the pre- and post-treatment using the paired t test. RESULTS We included 78 patients with visceral leishmaniasis, 44 males, with age ranging from 8 months to 13.5 years. Sixty-one patients were from Bahia. Fever and splenomegaly were present in 96.1% and 100% of the cases, respectively. The parasitological diagnosis was obtained in 74/78 patients: 67 patients through smear and/or culture of bone marrow (85.7%), five through liver biopsy and two through spleen puncture. The hematological findings and serum albumin presented significant improvement at the end of treatment (P<0.001), differently from serum gammaglobulin levels (P=0.087). There was predominance of IgG1 subclass, with two patients presenting low levels of IgG2. Initial treatment used antimoniate in 67 cases and amphotericin B in five. Eleven patients (15.7%) needed a second treatment, and were considered cured after it. There was significant improvement in the liver and spleen size at the end of the treatment (P<0.001). One patient presented spontaneous remission and five died due to bleeding. CONCLUSIONS In order to obtain accurate diagnosis and treatment, especially regarding health services of areas with low-incidence of visceral leishmaniasis, the diagnosis of patients with fever and visceromegaly, who come from endemic areas, should include visceral leishmaniasis.

Clinical and laboratorial features of visceral toxocariasis in infancy

Forty children with a diagnosis of Visceral Toxocariasis were evaluated prospectively from February 1982 to June 1989. Diagnosis was established by clinical, laboratory and serological (ELISA - ES Toxocara canis antigen) evaluations. A great clinical polymorphism was found in our patients, ranging from unspecific or absent manifestations to an exuberant symptomatology. The laboratory findings were: leukocytosis, eosinophilia and elevation of serum gammaglobulin and isohemagglutinin levels. No significant relationship between clinical findings and laboratory parameters was found. Serology (ELISA) was a method of great diagnostic support but did not show a correlation with clinical and laboratory findings in this study. There was a significant relationship between pulmonary manifestations and the presence of signs and/or symptoms, when the patients were sent to us. Our findings, especially the high incidence of pulmonary manifestations, suggest that Visceral Toxocariasis has to be included in the differential diagnostic of children with pulmonary manifestations, characteristic epidemiological data and associated eosinophilia.

Administration of live attenuated varicella vaccine to children with cancer before starting chemotherapy

From July 1985 to February 1987, of 46 consecutive children with cancer (26 male, 20 female; median age, 4 years) with no prior history of chickenpox, the initial 30 patients were randomized either to receive or not to receive live attenuated varicella vaccine (LAVV) before chemotherapy was started and the remaining 16 patients were all immunized without randomization. Before immunization, Varicella zoster (VZ) antibodies were detected by immunofluorescence and ELISA in 11 (34%) of 32 vaccinated children and two (14%) of 14 controls, indicating previous infection. A booster effect was evident in 70% of them and no side effects were noted. Ten (28%) of 32 vaccinees were excluded from the analysis because of early death due to cancer (1-4 weeks). Seroconversion was demonstrated in ten (77%) of 13 vaccinees, with high antibody titres. Only three of them lost their antibodies 2 years after immunization, as disclosed by serological follow-up. Eight out of 13 vaccinees had household contacts with VZ and none became infected. Zoster immunoglobulin (ZIG) was never given. Among controls, seven out of 14 were exposed to VZ and four (57%) became infected. Mild side effects were observed in four (12.5%) out of 32 vaccinees (three with papulovesicular rash, 6-30 lesions, and one with a 3-day intermittent fever). Local reactions, zoster and spreading of vaccinal virus did not occur. LAVV proved to be safe and effective when administered before starting chemotherapy to children with cancer and no history of varicella.

Hepatitis A antibodies in two socioeconomically distinct populations of São Paulo, Brazil

To evaluate the prevalence of antibody against hepatitis A in two socioeconomically distinct populations of a developing country, 540 serum specimens from children and adults living in Sao Paulo, Brazil, were tested for IgG anti HAV by a commercial radioimunoassay (Havab, Abbott Laboratories). The prevalence of anti-HAV in low socioeconomic level subjects was 75.0% in children 2-11 years old and 100.0% in adults, whereas in middle socioeconomic level significantly lower prevalences were observed (40.3% in chidren 2-11 years old and 91.9% in adults). Voluntary blood donors of middle socioeconomic level showed a prevalence of 90.4%. These data suggest that hepatitis A infection remains a highly endemic disease in Sao Paulo, Brazil.

Rubella Vaccination of Unknowingly Pregnant Women: The São Paulo Experience, 2001

BACKGROUND Rubella vaccination is contraindicated during pregnancy. During mass immunization of women of childbearing age against rubella, women unknowingly pregnant may be vaccinated. To evaluate the effects of rubella vaccination during pregnancy, the Brazilian state of São Paulo conducted a follow-up study of pregnant women vaccinated during a rubella campaign in 2001. METHODS Women vaccinated during pregnancy were reported to a national surveillance system. In the state of São Paulo, follow-up of vaccinated women included household interviews. Serum samples from vaccinated women were tested for antirubella antibodies to classify susceptibility to rubella infection. Children born to susceptible mothers were tested for evidence of congenital rubella infection and evaluated for signs of congenital rubella syndrome. RESULTS The São Paulo State Health Department received 6473 notifications of women vaccinated during pregnancy. Serology performed for 5580 women identified 811 (15%) that were previously susceptible. Incidence of spontaneous abortion or stillbirth among previously susceptible vaccinated women was similar to women with prior immunity. Twenty-seven (4.7%) of 580 newborns tested had evidence of congenital rubella infection; none had congenital rubella syndrome. CONCLUSIONS Mass rubella vaccination of women of childbearing age was not associated with adverse birth outcomes or congenital rubella syndrome among children born to women vaccinated during pregnancy.

Análise crítica das recomendações do uso das vacinas meningocócicas conjugadas

OBJECTIVES To assess the epidemiology of meningococcal disease (MD) in Brazil and the impact that recent evidence and lessons learned from the introduction of meningococcal C conjugate (MCC) vaccines into immunization programs may have on different strategies of vaccine use. SOURCES Non-systematic review of the MEDLINE, SciELO and LILACS databases covering the period from 2000 to 2011. SUMMARY OF THE FINDINGS Meningococcal disease is endemic in Brazil, with periodic occurrence of outbreaks. Most cases are associated with serogroup C and the highest incidence rates are observed in infants, encouraging the introduction of MCC vaccine in the National Immunization Program in 2010 for children under 2 years old. The introduction of MCC vaccines into immunization programs in Europe, Canada and Australia proved to be effective, with dramatic reduction in the incidence of serogroup C meningococcal disease, not only in the vaccinated, but also in the unvaccinated individuals. Long-term effectiveness of MCC vaccines was dependent on a combination of antibody persistence, immunologic memory and herd protection. Recent evidence indicating that antibody persistence is not long-lasting in young immunized children, and that immunologic memory is not fast enough to protect them against the disease, emphasize the importance of herd protection to maintain the population protected. CONCLUSIONS The rapid decline of antibody titers in children vaccinated in the first years of life suggests the need to incorporate booster doses before adolescence, especially in locations like Brazil, where the immunization program did not incorporate catch-up campaigns including adolescents, lacking the herd immunity effect.OBJECTIVES: To assess the epidemiology of meningococcal disease (MD) in Brazil and the impact that recent evidence and lessons learned from the introduction of meningococcal C conjugate (MCC) vaccines into immunization programs may have on different strategies of vaccine use. SOURCES: Non-systematic review of the MEDLINE, SciELO and LILACS databases covering the period from 2000 to 2011. SUMMARY OF THE FINDINGS: Meningococcal disease is endemic in Brazil, with periodic occurrence of outbreaks. Most cases are associated with serogroup C and the highest incidence rates are observed in infants, encouraging the introduction of MCC vaccine in the National Immunization Program in 2010 for children under 2 years old. The introduction of MCC vaccines into immunization programs in Europe, Canada and Australia proved to be effective, with dramatic reduction in the incidence of serogroup C meningococcal disease, not only in the vaccinated, but also in the unvaccinated individuals. Long-term effectiveness of MCC vaccines was dependent on a combination of antibody persistence, immunologic memory and herd protection. Recent evidence indicating that antibody persistence is not long-lasting in young immunized children, and that immunologic memory is not fast enough to protect them against the disease, emphasize the importance of herd protection to maintain the population protected. CONCLUSIONS: The rapid decline of antibody titers in children vaccinated in the first years of life suggests the need to incorporate booster doses before adolescence, especially in locations like Brazil, where the immunization program did not incorporate catch-up campaigns including adolescents, lacking the herd immunity effect.

Varicella vaccines and measles, mumps, rubella, and varicella vaccine.

OBJECTIVES To present an up-to-date review of studies investigating the efficacy, adverse events and vaccination regimens of the varicella vaccine and the new presentation combined with the vaccine for measles, mumps and rubella. SOURCES OF DATA Bibliographic review of the MEDLINE and LILACS databases covering the period 1999 to 2006. SUMMARY OF THE FINDINGS The varicella vaccine protects 70 to 90% of immunized children against any form of varicella zoster infection, but the efficacy against severe forms is higher (95 to 98%). This is a well-tolerated vaccine that causes few reactions. Since the vaccine was licensed, there have been three confirmed cases of transmission of the vaccine virus by domestic contacts to previously healthy people, who went on to develop mild disease. Despite evidence that the protection offered by this vaccine can wane over a number of years, it is not yet possible to state that a second dose is warranted, bearing in mind exposure to wild virus. After universal vaccination the chances of natural stimulation should drop and it is very probable that booster doses will become necessary. A measles, mumps, rubella, and varicella vaccine has recently been licensed that combines vaccines for measles, mumps, rubella and varicella in a single product with high rates of seroconversion. CONCLUSIONS The Brazilian Society of Pediatrics recommends the varicella vaccine for children from 1 year on. We hope that the measles, mumps, rubella, and varicella vaccine will soon be available in Brazil, since combined vaccines facilitate wider vaccination coverage.