pertussis vaccination

Last edited 04/2019

Pertussis vaccination is a suspension of killed organisms.

Pertussis in the very young is a significant cause of illness and death

• majority of hospitalisations occur in infants under six months of age, some of whom are seriously ill and require admission to paediatric intensive care units
• during the period 2001-2011, there were 48 deaths due to pertussis in infants of less than one year of age in England. Of these deaths, 41 occurred in infants who were too young to be protected by vaccination

Pertussis vaccination is the classic example of the importance of a high uptake rate and of herd immunity required to make a vaccination program successful

• in 1950 in the UK there were 100,000 cases of whooping cough. By 1973, with greater than 80% uptake of vaccine this had fallen to 2400. However, in the mid 1970s public anxiety about the possible side effects of the vaccine led to a fall in uptake to 30%, with an increase in the number of cases to 1950 levels once more
• in 1988, with better public understanding of the relative risks of the vaccination and the disease itself, the uptake was 73%, and there were 5000 cases of whooping cough in the UK
• since 1992, coverage has been consistently 92% or higher by the second birthday and pertussis notifications fell to fewer than 5,000 per year. During the period 2000-2011 there were 1,500 cases or less notified annually
• despite sustained levels of vaccine coverage above 95% from 2010, an increase in pertussis activity was observed in England and Wales from October 2011 and continued into 2012, initially affecting adolescents and adults and later extending to young infants. As a result, a national outbreak was declared in April 2012
• in recent years, the introduction of new diagnostic methods, and widespread use of serology testing in particular, has improved the ascertainment of laboratory confirmed pertussis in older children and adults

The acellular vaccines are made from highly purified selected components of the Bordetella pertussis organism

• the vaccine differ in source, number of components, amount of each component, and method of manufacture, resulting in differences in efficacy and in the frequency of adverse effects
  
  
• changed from whole-cell to acellular pertussis vaccines in 2004, a five component vaccine (Pediacel), which contains pertussis toxoid (PT), filamentous haemagglutinin (FHA), fimbrial agglutinogens (FIM) 2 and 3, and pertactin (PRN) was chosen
  • vaccine had been shown to offer equal or better protection against clinically typical pertussis disease than the whole-cell pertussis vaccine previously used in the UK
  • a three-component vaccine (Infanrix IPV+Hib) containing PT, FHA and PRN was available for primary immunisation, this was not used because of limited data on efficacy
    • subsequent analysis suggested that the cohorts who had Infanrix+Hib, a similar vaccine with the same 3aP components, which was used in the UK in 1999-2001 because of a shortage of whole-cell vaccine, were as well protected up to the age of the pre-school booster as those cohorts who had been eligible for whole-cell or 5aP vaccines in infancy
    • in 2010, the World Health Organisation reviewed all the global data on pertussis control in countries using acellular vaccines. They concluded that acellular pertussis vaccines with three or more components have higher protective efficacy than vaccines with fewer components, but did not find consistent evidence of a difference between three and five components
    • on the basis of this evidence, both three- and five-component pertussis-containing vaccines are now considered suitable both for primary immunisation and for pre-school boosting in the UK

The pertussis vaccines are only given as part of combined products:

• diphtheria/tetanus/acellular pertussis/inactivated polio vaccine/ Haemophilus influenzae type b/Hepatitis B(DTaP/IPV/Hib/Hepatitis B) - for primary immunisation
• diphtheria/tetanus/acellular pertussis/inactivated polio vaccine/ (DTaP/ IPV or dTaP/IPV) - for pre-school booster
• diphtheria/tetanus/acellular pertussis/inactivated polio vaccine (dTaP/ IPV) - for pregnant women

Check uptodate details in the The Green Book before prescribing/administering a vaccine.

Check the Summary of Product Characteristics (SPC) before prescribing/administering a vaccine.

Routine childhood immunisations

For the routine childhood immunisation schedule:

• First dose of 0.5ml of a pertussis-containing vaccine at two months of age
• Second dose of 0.5ml at three months of age (one month after the first dose)
• Third dose of 0.5ml at four months of age (one month after the second dose)
• A fourth dose of 0.5ml should be given as part of the pre-school booster (three years four months old or soon after)

Difference Between DTaP and dTaP

• Diphtheria vaccines are produced in two strengths according to the diphtheria toxoid content:
  • vaccines containing the higher dose of diphtheria toxoid (abbreviated to 'D') contain not less than 30IU
  • vaccines containing the lower dose of diphtheria toxoid (abbreviated to 'd') contain approximately 2IU

Reference:

• (1) Immunisation Against Infectious Disease - "The Green Book". Chapter 24.Pertussis (April 2019)
• (2) Immunisation Against Infectious Disease - "The Green Book". Chapter 15. Diptheria (April 2019)