The effects of immunisation upon the natural history of pertussis. A family study in the Cardiff area.

Abstract

SUMMARY During an outbreak of pertussis in the Cardiff area in 1974, 229 children with the disease were studied to assess the effect of immunisation upon its natural history and severity. The typical clinical features of pertussis, such as paroxysmal cough, whooping, vomiting, cyanosis, and irregular breathing, were less prevalent in both the immunised and the older children. Immunisation is the main factor in protecting against complications such as fits; and, together with older age, it protects against hospitalisation. Nevertheless, pertussis today can be just as severe as it was 40 years ago, and the vaccine remains the major factor ameliorating its natural history. The immunisation programme needs more active support by all child health workers.In 1974, public concern about the adverse complications of pertussis immunisation, with the consequent fall in the acceptance of immunisation, coincided with an outbreak of pertussis in the Cardiff area. This permitted a study of a considerable number of cases of the disease in both immunised and non-immunised children. This report is concerned with the effectiveness of the immunisation as measured by the severity of the disease in immunised and non-immunised children who contracted it. Patients and MethodsThe study population consisted of children up to the age of 16. They were either notified cases of pertussis, or affected contacts who had not been notified to the Medical Officer for Environmental Health (MOEH). A questionnaire was used to record details of the clinical manifestation of the disease. The original hospital notes of patients admitted to hopital were studied. Each child was visited three times or more. The immunisation history of each child was checked with records in the health authority offices and with general practitioners' records. A child was considered to have been fully vaccinated if a written record was found showing a completed primary course of three injections. Fourth and fifth injections, if given, were counted as boosters.If the case was clinically identified before or during the fourth week from the beginning of the disease, a swab was taken from the surface of the nasopharynx and immediately cultured on BordetGengou media (Oxoid CM267). The plates were then sent to the public health laboratory for bacteriological identification (Bradford et al., 1946). Virological investigation was not undertaken. ResultsThe study consisted of 229 children in 145 families, diagnosed and treated for pertussis. Notifications to the MOEH provided 89 children (39%). The remaining 140 children (61 %) were siblings, or other contacts, with pertussis, discovered as a result of visits to the families. Of the 229 children studied, 45 % were boys, more than 80% were under six years old, and 44 % were under two years old.Vaccination records showed that 116 (51 Y.) had not been vaccinated, 101 (44%) were fully vaccinated, and 12 (5%) were partially vaccinated. Nasopharyngeal swabs were obtained from 44 (19 %); one-quarter of these yielded Bordetella pertussis on c...

Reduced Severity of Pertussis in Persons With Age-Appropriate Pertussis Vaccination—United States, 2010–2012

“…Findings from our study are consistent with an analysis by Barlow et al, which demonstrated that pertussis patients aged 6 weeks to 18 years who had ever received pertussis vaccination were less likely to be hospitalized or to develop severe illness [18]. Importantly, and in contrast to prior studies that focused exclusively on children age 18 and under [18–26], our analysis also included adults. We found that the protective effect of pertussis vaccination against more serious disease extends to adults, demonstrating that, although acellular pertussis vaccines have a diminished duration of protection from infection compared with whole-cell vaccines, both the childhood and adult ACIP pertussis vaccine recommendations lead to a reduction in the clinical severity of pertussis across all age groups.…”

“…Previous analyses have suggested that pertussis infection is less severe in immunized children [18–26]; however, most of these studies were conducted in primarily whole-cell primed populations and many had sample sizes too small to fully assess confounding variables such as age, which is highly associated with both vaccination status and severity of pertussis illness. An exception is a recent analysis by Barlow et al which found that vaccinated children and adolescents in the Portland, Oregon metropolitan area, who had received primarily acellular vaccine, had decreased severity and duration of illness compared to unvaccinated peers [18].…”

Natural course of 500 consecutive cases of whooping cough: a general practice population study

“…Vesselinova-Jenkins et al found that 8.3% developed pneumonia, 7% had convulsions, and 22% were admitted to hospital 3. A study based on notified cases in a similar area found a much lower rate of complications and a hospital admission rate of 2.8%,4 while another study of 8000 notified cases showed a hospital admission rate of 10% 5.…”

Pertussis clinical case definition: Time for change in developing countries?

“…al . had noted a higher prevalence of facial congestion compared to the other symptoms [25]. Furthermore, pertussis was more likely to occur in age less than 6 months, similar to Northern Iran and Spain [26, 27].…”