Research and analysis

HPR volume 9 issue 17: news and travel (15 May)

Updated 29 December 2015

1. Laboratory confirmed pertussis in England: data to end-February 2015

This report presents current pertussis activity to 28 February 2015, updating the previous report that included data to the end of October 2014 [1].

1.1 Background

In England the number of laboratory confirmed cases of pertussis has fallen overall each consecutive year from a peak of 9,367 cases in 2012; by 51% between 2012 and 2013 (4,621 cases) and 27% between 2013 and 2014 (3,388 cases). An expected seasonal increase was seen in August and September 2014. The number of laboratory confirmed cases reported in February 2015 was 21% higher than the previous month and 36% higher than the same period in 2014. Overall pertussis activity in England persists at raised levels compared to the years preceding the outbreak in 2012*.

The pertussis vaccination in pregnancy programme was introduced in October 2012 [2,3] in response to a national outbreak* and is offered to women ideally between 28 to 32 weeks pregnancy to protect infants in their first few weeks of life. Confirmed pertussis cases in infants <6 months of age have remained low despite the continued high activity in other age groups**.

The immunisation programme for pregnant women continues to be important, particularly in light of the ongoing raised levels of pertussis in those from 1 year of age and recent infant deaths. There have been recent key publications on the high effectiveness and safety of the pertussis immunisation in pregnancy programme [4,5,6]. Together with coverage and epidemiological data, these findings informed the Joint Committee on Vaccination and Immunisation’s decision in July 2014 that the pregnancy programme should continue for at least a further 5 years [7].

Pertussis vaccination coverage in pregnant women has been published up to December 2014 when 62% coverage was recorded [8] and a seasonal pattern in uptake has been observed in both 2013 and 2014 peaking in December each year.

1.2 Confirmed cases in 2015

In infants under 3 months of age low numbers of cases have been sustained since December 2012 with fewer than 10 cases per month reported up to August 2013 and 6 or fewer reported each month between September 2013 and March 2014. Cases increased from April 2014, in line with expected seasonal increases, peaking at 21 cases in July 2014; the highest number of monthly cases since 23 reported in November 2012.

Pertussis activity in all infants <1 year of age was very low in the first 2 months of 2015***; disease incidence, as expected, continued to be highest in this age group but case reports are now in line with those seen before the 2012 peak. The numbers of laboratory confirmed cases in those aged 1 year and older, however, continue to be higher than reported before the 2012 outbreak.

Overall confirmed pertussis cases were higher to February 2015 than in comparable periods in previous years, excluding 2013 when high levels of disease were starting to fall from the peak in autumn 2012. There had been no deaths reported in infants with laboratory confirmed pertussis in 2015 as at end-February.

1.3 Overall trends as at end-February 2015

The greatest reduction in disease since the peak in 2012 has been in infants aged under 6 months. Ten deaths had been reported in young babies with confirmed pertussis who were born after the introduction of the pregnancy programme on 1 October 2012, as at end February. Nine of these 10 babies were born to mothers who had not been vaccinated against pertussis, all of the 10 babies were too young to be fully protected by vaccination themselves and none had received their first dose of pertussis-containing vaccine.

* See figure in the PDF version of this issue of HPR.

** See table 1 in the PDF version of this issue of HPR.

*** See table 2 in the PDF version of this issue of HPR.

1.4 References

1. Laboratory confirmed pertussis in England: data to end-October 2014. HPR 8(47): news (12 December 2014).
2. “Pregnant women to be offered whooping cough vaccination”, 28 September 2012. Department of Health website.
3. “HPA welcomes introduction of whooping cough vaccination for pregnant women as outbreak continues” HPA press release, 28 September 2012.
4. Amirthalingam G, Andrews N, Campbell H et al (2014). Effectiveness of maternal pertussis vaccination in England: an observational study Lancet.
5. Donegan K, King B, Bryan P (2014). Safety of pertussis vaccination in pregnant women in the UK: observational study British Medical Journal.
6. Dabrera G, Amirthalingam G, Andrews N et al (2014).A case-control study to estimate the effectiveness of maternal pertussis vaccination in protecting newborn infants in England and Wales, 2012–2013 Clinical Infectious Diseases (online), 19 October.
7. JCVI minutes.
8. Pertussis Vaccination Programme for Pregnant Women: vaccine coverage estimates in England (PHE statistics).

2. WHO Emergency Committee updates wild poliovirus vaccination recommendations

A fifth meeting of the World Health Organization’s International Health Regulations Emergency Committee – convened on 5 May to review progress on implementation of temporary measures on international spread of wild poliovirus – concluded that the situation still constitutes a Public Health Emergency of International Concern (PHEIC) and recommended the extension of the Temporary Recommendations for a further 3 months [1].

Vaccination recommendations for travellers to countries exhibiting active transmission of wild polio virus (WPV) – first issued under the International Health Regulations (IHR) by the WHO in May last year – remain in place.

Affected countries now fall into 3 groups:

• those that are still currently ‘exporting’ WPV (Afghanistan and Pakistan)
• those infected but no longer exporting (Cameroon, Equatorial Guinea, Nigeria, Somalia and Iraq)
• states no longer affected but which remain vulnerable to international spread (Ethiopia, Syria and Israel)

The WHO-IHR emergency committee noted that strong progress had been made since the declaration of the PHEIC one year ago. In Pakistan, for example, since last November, an average of 370,000 international travellers per month have been vaccinated pre-departure at health facilities and points of exit. However, international spread of WPV has continued and the WHO committee concluded that: stronger cross-border vaccination and surveillance activities were required in Pakistan and Afghanistan, in particular, and that these two countries should be treated as a single epidemiological block in view of the frequent cross-border population movement (poliovirus isolates found in cases in Pakistan were shown to be closely related to strains circulating in Afghanistan).

Up-to-date vaccination recommendations for travellers to affected countries from England, Wales and Northern Ireland, endorsed by the Department of Health for England, have been issued by the PHE-commissioned National Travel Health Network and Centre (NaTHNaC) [2].

Since WHO recommended that both Afghanistan and Pakistan should continue to require all departing residents or long-term visitors to be vaccinated, NaTHNaC has reiterated that visitors leaving either country may be required to produce a valid vaccination certificate at the time of their departure [2].

NaTHNaC has reminded clinicians in the UK that they should maintain awareness for suspect cases of poliomyelitis in travellers and migrants arriving from affected areas. Acute poliomyelitis is a notifiable disease. All suspected cases must be notified to the Proper Officer, normally the Consultant in Communicable Disease Control in the Health Protection Team of the local PHE Centre, which are then reported to the Centre for Infectious Disease Surveillance and Control.

2.1 References

1. WHO statement on the fifth IHR Emergency Committee meeting regarding the international spread of wild poliovirus (5 May 2015).
2. National Travel Health Network and Centre clinical update: Afghanistan: evidence of polio spread to Pakistan and polio vaccine recommendations for travellers (13 May 2015).