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P Waight

Publications and source records attributed to P Waight.

At least 19 recordsLinked to original sources
PubMed2007

Risks of convulsion and aseptic meningitis following measles-mumps-rubella vaccination in the United Kingdom.

Measles-mumps-rubella (MMR) vaccines containing the Urabe strain of mumps were withdrawn in the United Kingdom in 1992 following demonstration of an increased risk of aseptic meningitis 15-35 days after vaccination. Following introduction of a replacement MMR vaccine (Priorix; GlaxoSmithKline, London, United Kingdom) in 1998, active surveillance of aseptic meningitis and convulsion was established to evaluate the risk associated with the new vaccine. No laboratory-confirmed cases of mumps meningitis were detected among children aged 12-23 months after administration of 1.6 million doses of Priorix (upper 95% confidence limit of risk: 1:437,000) in England and Wales. The upper 95% confidence limit excluded the risk found for mumps meningitis with Urabe vaccines (1:143,000 doses). No cases of aseptic meningitis were detected among children aged 12-23 months, who had received over 99,000 doses of Priorix (upper 95% confidence limit of risk: 1:27,000), in a regional database of hospital-admitted cases. This compares with an observed risk of 1:12,400 for Urabe vaccines. An elevated relative incidence of convulsion was found in the 6- to 11-day period after receipt of Priorix (relative incidence = 6.26, 95% confidence interval: 3.85, 10.18)-consistent with the known effects of the measles component of MMR vaccine-but not in the 15- to 35-day period (relative incidence = 1.48, 95% confidence interval: 0.88, 2.50) as occurred with Urabe-containing vaccines. This study demonstrates the power of active postmarketing surveillance to identify or exclude events too rare to be detected in prelicensure trials.

England↗
PubMed2006

Similar long-term vaccine efficacy of two versus three doses of HBV vaccine in early life.

WHO currently recommends three vaccinations against hepatitis B to provide optimal protection against infection and carriage. However, immunological theory and mathematical modelling suggest that similar protection could be induced with two doses, and trials among adolescents and adults have shown comparable rates for both primary seroprotection and geometric mean titres following vaccination. We determined vaccine efficacy among 60 children who only received two doses of hepatitis B vaccine as infants and among 463 children who had received three doses after 4-7 years of follow-up. Vaccine efficacy among the two-dose group was 86.3% against anti-HBc positivity (infection) and 92.3% against HBsAg positivity (carriage), which was similar to the vaccine efficacy found among the participants who had received three doses. To confirm this comparable vaccine efficacy a randomised controlled non-inferiority trial with long-term follow-up is needed.

Child, Preschool↗
PubMed2006

Long-term protection against carriage of hepatitis B virus after infant vaccination.

BACKGROUND: Carriage of hepatitis B virus (HBV) is a major risk factor for liver cirrhosis and hepatocellular carcinoma. Infant vaccination has been effective in preventing horizontal transmission during early childhood. It is unknown whether protection is maintained into early adulthood. METHODS: In 1984, early childhood vaccination was introduced in 2 rural Gambian villages. In 2003, serological assessment of 81.5% of 1,350 eligible participants 1-24 years old was done, to determine vaccine efficacy against infection and carriage. RESULTS: Overall vaccine efficacy against infection and carriage was 83.4% (95% confidence interval [CI], 79.8%-86.6%) and 96.5% (85% CI, 93.9%-98.9%), respectively. Vaccine efficacy against infection was similar when restricted to primary responders (85.3%), but a significant effect of peak antibody concentration was found. Both vaccine efficacy and levels of hepatitis B surface antibody (anti-HBs) decreased with age, resulting in a vaccine efficacy against infection and carriage among 20-24-year-old participants of 70.9% (95% CI, 60.4%-80.5%) and 91.1% (95% CI, 75.8%-100%), respectively. Fifteen years after vaccination, fewer than half of the vaccinees had detectable anti-HBs. The prevalence of carriage in the unvaccinated population was similar to the prevalence 20 years earlier. CONCLUSIONS: HBV vaccination early during life can provide long-lasting protection against carriage, despite decreasing antibody levels. The role played by subclinical boosting and the necessity of a booster need to be evaluated.

Adolescent↗
PubMed2003

Bacterial infections, immune overload, and MMR vaccine. Measles, mumps, and rubella.

Combined measles, mumps, and rubella (MMR) vaccine did not increase the risk of hospitalisation with invasive bacterial infection in the three months after vaccination; rather there was a protective effect. These results provide no support for the concept of "immunological overload" induced by multiple antigen vaccinations, nor calls for single antigen vaccines.

Bacterial Infections↗
PubMed2002

Recall bias, MMR, and autism.

Parents of autistic children with regressive symptoms who were diagnosed after the publicity alleging a link with measles, mumps, and rubella (MMR) vaccine tended to recall the onset as shortly after MMR more often than parents of similar children who were diagnosed prior to the publicity. This is consistent with the recall bias expected under such circumstances.

Attitude to Health↗
PubMed2001

Immunogenicity and reactogenicity of acellular diphtheria/tetanus/pertussis vaccines given as a pre-school booster: effect of simultaneous administration of MMR.

Four acellular diphtheria/tetanus/pertussis (aDTP) vaccines were compared with two diphtheria/tetanus (DT) vaccines given as a pre-school booster to 1033 children aged 4 to < 6 years who had completed primary immunisation with DTP vaccine according to the UK 2, 3 and 4 month schedule; 71 children had received aDTP vaccine and the remaining 962 a whole cell DTP vaccine for primary immunisation. The effect of simultaneous administration of a second dose of MMR vaccine was evaluated in 374 (37%). Overall, there was little difference in the frequency of post-vaccination symptoms in DT and aDTP vaccinees, although local reactions occurred more quickly in the aDTP group. The concomitant administration of MMR had no effect on local reactions or fever within 10 days, or on the proportions requiring a doctor's visit in the 4--6 week post-vaccination period. Local reactions > or = 3 cm were higher on day 2 in children who had received aDTP for primary immunisation (erythema 32.4% vs. 17.4% for wDTP, P = 0.0012; swelling 28.2% vs. 15.5%, P = 0.0027). Pertussis antibody responses were consistent with the antigen content of the aDTP vaccines. All were more immunogenic with respect to PT -- the only pertussis antigen which by itself has been shown to be protective in clinical trials -- than a wDTP pre-school booster given in an earlier trial. MMR vaccine had no significant effect on antibody responses to either the pertussis or diphtheria and tetanus antigens. Diphtheria antibody responses in children who had received wDTP for primary immunisation were 2.8 times higher than in those who had received aDTP vaccine (P < 0.0001); they were also higher in children who had received a single dose of a Haemophilus influenzae type b vaccine containing CRM(197) conjugate after 12 months of age. For countries currently using DT vaccines as a pre-school booster, replacement with an aDTP vaccine is unlikely to have a perceptible effect on reactogenicity, at least in children given wDTP for primary immunisation, and would boost antibody levels to antigens known to be associated with protection.

Child, Preschool↗
PubMed2001

Does oral polio vaccine cause intussusception in infants? Evidence from a sequence of three self-controlled cases series studies in the United Kingdom.

BACKGROUND: The use of live oral poliomyelitis vaccine (OPV) has led to the elimination of poliomyelitis disease in many countries since licensure in 1960. The discovery of an increased risk of an intestinal obstruction known as intussusception following live rotavirus vaccination raised questions about the possibility of a link between live OPV and intussusception. METHODS: Three self-controlled case-series studies were carried out. The first was exploratory and included 218 intussusception episodes from hospital admissions data linked to vaccination records in the Thames region. The two subsequent studies, which used further hospital admissions data and the General Practice Research Database (GPRD) included 107 and 198 episodes respectively and were used to test hypotheses generated in the first study. RESULTS: In the exploratory study risk periods of up to 6 weeks after each dose were examined. The only period with some evidence of an increased risk was the 14-27-day period after the third dose (relative incidence (RI) = 1.97, p = 0.011). The second hospital admissions study and the GPRD study showed no evidence of an increased relative incidence in any putative risk period and did not confirm the increased risk in the 14-27-day period after dose 3 with a combined RI of 1.03. CONCLUSIONS: The sequence of studies does not support the hypothesis that OPV causes intussusception. The increased RI in the first study may be explained as a chance finding due to the number of risk periods examined and highlights the need for caution when looking at many risk periods without an a priori hypothesis.

Chi-Square Distribution↗
PubMed2001

Idiopathic thrombocytopenic purpura and MMR vaccine.

A CAUSAL ASSOCIATION BETWEEN MEASLES: mumps-rubella (MMR) vaccine and idiopathic thrombocytopenic purpura (ITP) was confirmed using immunisation/hospital admission record linkage. The absolute risk within six weeks of immunisation was 1 in 22 300 doses, with two of every three cases occurring in the six week post-immunisation period being caused by MMR. Children with ITP before MMR had no vaccine associated recurrences.

Female↗
PubMed2000

Invasive pneumococcal disease in England and Wales: vaccination implications.

Knowledge of the epidemiology of invasive pneumococcal disease (IPD) will aid in planning the use of pneumococcal vaccines. A United Kingdom (UK)-based surveillance in England and Wales (1995-1997) of 11,528 individuals with IPD and a local enhanced surveillance in the Oxford (UK) area (1995-1999) have been analyzed. IPD has a high attack rate in children, with 37.1-48.1 cases per 100,000 infants <1 year old per year, and in older persons, with 21.2-36.2 cases per 100,000 persons >65 years old per year, for England, Wales, and Oxford. The 7-valent conjugate vaccine includes serotypes causing < or =79% of IPD in children <5 years old, but only 66% in adults >65 years old. The data also indicate that IPD varies by serotype, age, and country, emphasizing that the epidemiology of IPD is heterogeneous and requires continued surveillance.

Adolescent↗
PubMed2000

Epidemiology of invasive and other pneumococcal disease in children in England and Wales 1996-1998.

UNLABELLED: The results of enhanced national surveillance of pneumococcal disease in children < 15 y of age in England and Wales are reported for the period 1996-1998. Of the 1985 cases of laboratory-confirmed invasive disease (annual incidence 6.6 per 100,000 overall and 39.7 per 100,000 in infants < 1 y of age), 485 (24%) were meningitis (annual incidence of 1.6 per 100,000 overall and 15.7 per 100,000 in infants <1 y of age). Fifty-nine deaths in children with invasive disease were identified-3% of the total reports. Thirty-one different serogroups/types were identified, with organisms in the 7-valent conjugate vaccine responsible for 69% of the infections in children < 5 y of age: this rose to 77% and 82%, respectively, for the 9-and 11-valent vaccines. Resistance to penicillin varied from 2.3% to 6.2% in different years, but erythromycin resistance remained constant at 17%. The vast majority of resistant isolates were in vaccine serotype/groups. Computerized hospital admission records for all children < 15 y of age with a discharge diagnosis code indicating probable pneumococcal disease were also analysed for 1997. The annual incidence for cases with a code specifically mentioning S. pneumoniae was 9.9 per 100,000 compared with 71.2 per 100,000 for lobar pneumonia; the mean duration of stay for both was < 1 wk. The incidence of admission for pneumococcal meningitis (1.9 overall and 19.6 for infants < 1 y of age) was similar to that derived from laboratory reports and resulted in an average duration of stay of 2 wk. CONCLUSION: This surveillance has confirmed the substantial burden of morbidity attributable to pneumococcal disease in British children and the potential public health benefits that could be achieved by the use of pneumococcal conjugate vaccines.

Adolescent↗
PubMed1998

Pneumococcal bacteraemia and meningitis in England and Wales, 1993 to 1995.

A total of 10,346 blood and 682 cerebrospinal fluid (CSF) isolates of Streptococcus pneumoniae were reported to the PHLS Communicable Disease Surveillance Centre from laboratories in England and Wales from 1 January 1993 to 31 December 1995. This corresponds to a mean annual incidence of 6.7 per 100,000 episodes of bacteraemia and 0.44/100,000 of meningitis. Absolute numbers of pneumococcal bacteraemia were similar to levels reported between 1990 and 1992, but fewer isolates of pneumococci were made from CSF. There was no discernible overall trend between 1993 and 1995, but age specific incidence suggested a slight increase in bacteraemia in older age groups. Estimated case fatality rates were 20% for pneumococcal bacteraemia and 22% for meningitis. The proportion of pneumococcal strains resistant to penicillin and erythromycin rose between 1989 and 1995 from 0.3% to 2.9% and 3.3% to 10.9%, respectively. The persistent threat of invasive pneumococcal infections highlights the need for continuing laboratory surveillance (including serotyping), appropriate use of antibiotics, and immunisation of groups at risk. The development of conjugate vaccines offers new prospects for prevention.

Adolescent↗
PubMed1998

Safety assessment post-licensure.

The objectives of post-licensure surveillance are to identify rare or novel adverse events, estimate their rate of occurrence and distinguish those that are causally related to vaccination. Evidence of causality is based on biological plausibility supported by laboratory evidence of vaccine involvement and/or a statistically significant excess of events in the post-vaccination period. Passive reporting systems have methodological limitations, particularly for ascertaining reliable adverse event rates and investigating causal relationships. In Canada, an active surveillance system (IMPACT) has been established in sentinel paediatric hospitals where nurses scrutinise all admissions for conditions conforming to a defined set of adverse events. While ascertainment of events resulting in hospital admission should be complete, causality is difficult to assess without information on the incidence of such events outside the post-vaccination risk period. The use of computerised data bases which link clinical events with immunisation records have allowed the risk of events such as convulsions attributable to DTP, MMR and Hib vaccines to be defined. The record linkage method promises to be a useful method for routine surveillance of vaccine safety.

Adverse Drug Reaction Reporting Systems↗
PubMed1997

The epidemiology of rubella in England and Wales before and after the 1994 measles and rubella vaccination campaign: fourth joint report from the PHLS and the National Congenital Rubella Surveillance Programme.

The national immunisation campaign carried out in the United Kingdom in November 1994 was designed to give children aged 5 to 16 years of age a single dose of a combined measles and rubella vaccine. Its main objective was to prevent an epidemic of measles predicted in school age children. The rubella component of the vaccine was included in order to reduce the high level of susceptibility to rubella in young adult males and thus reduce the risk of transmission from this group to pregnant women. Susceptibility to rubella in children aged 5 to 16 years has fallen from 15.7% to 3.4% since the measles and rubella campaign. Despite this the incidence of laboratory confirmed rubella rose substantially in 1996, largely on account of cases among males aged 17 to 24 years, who were not vaccinated in the 1994 campaign and about 16% of whom are susceptible. The impact of the resurgence on the incidence of infection in pregnancy has been relatively limited, due to the low level of susceptibility in the antenatal population (2% in nulliparous and 1.2% in parous women for 1994/5). No cases of congenital rubella arising from administration of measles and rubella vaccine during the campaign have been identified. The numbers of babies born with congenital rubella and terminations of pregnancy for rubella arising from the 1996 resurgence are expected to be similar to those that followed the 1993 resurgence. The reduction in susceptibility in future cohorts of young men who received measles and rubella vaccine in the 1994 campaign should prevent future resurgences after the year 2000. If a second dose of measles, mumps, and rubella (MMR) vaccine had not been introduced, susceptibility levels in the school age population would have risen to about 12% in the future. The effect of the second dose of MMR vaccine introduced for children aged 4 to 5 years in October 1996 will be assessed through serological surveillance.

Adolescent↗
PubMed1995

Cytomegalovirus infection in England and Wales: 1992 and 1993.

Cytomegalovirus causes illness through primary infection but also remains latent within the host and may be reactivated, especially if immunity is impaired. We have examined reports of cytomegalovirus infection from laboratories in England and Wales received by the PHLS Communicable Disease Surveillance Centre in 1992 and 1993. A total of 2938 reports were received, and 103 people had recurrent infections within the study period. The age distribution had peaks in infants (< 1 year of age) and in people aged 25 to 34 years. In almost a half of the patients (1371; 49%) factors were reported that indicated impaired immunity. Eighty-three of the 103 with recurrent infection (81%) were also reported to have impaired immunity. Children under 5 years accounted for 18% (543/2938) of reports. There were 930 reports of infections in people over 5 years of age who were not reported as immunocompromised. The data presented confirm that cytomegalovirus causes substantial morbidity in young children and people with impaired immunity. Cytomegalovirus infection causes considerable morbidity, especially hepatic, in patients whose immunity is thought to be normal.

Adolescent↗