No 28/31 - 2023

New temporary free whooping cough vaccination offer for pregnant women

Due to the currently increased whooping cough prevalence, EPI-NEWS 27/2023, the Danish Minister of Health has decided to introduce a new temporary free whooping cough vaccination offer for pregnant women in Danish). The offer comes into effect on 1 August 2023 and remains available through 31 December 2023, after which the intention is to make the offer permanent upon recommendation by the Danish Health Authority (in Danish).

The temporary offer was originally introduced as per 1 November 2019 based on the latest whooping cough epidemic in 2019-20. The offer was extended repeatedly, but eventually ended by the end of March 2023 at a point in time when whooping cough was experiencing a prolonged lull in Denmark. On this basis, it has also been difficult ascertain the effect of the whooping cough programme for pregnant women in Denmark, but various international studies have documented that the intervention is safe and effective.

Now, however, whooping cough has returned with 104 detected cases in May and 293 cases in June. As per 27 July, a total of 228 cases had been detected in July. Despite the slightly lower number of detected cases in July, an increase was recorded in the number of cases among 0-year-olds. In June and July, a total of 7 and 12 cases, respectively, were detected among 0-year-olds. Ten of the detected cases occurred in children below 3 months of age (3 cases in June and 7 cases in July). The remaining 9 detected cases in June and July were children aged 3-12 months, 7 of whom had been vaccinated in accordance with recommendations at 3 and 5 months of age. The lower number of detected cases in July may be owed to fewer medical appointments and diagnostics in this vacational period.

Many children below 6 months of age require admission to hospital if they are affected by whooping cough. Fortunately, serious complications are rare and fatalities even rarer, EPI-NEWS 27/2023.

The objective of whooping cough vaccination during pregnancy is to protect neonates in their first months of life until the child can be vaccinated, thereby preventing hospitalisation of the child.

The Danish Health Authority recommends that vaccination of pregnant women be given during the 2nd and 3rd routine pregnancy examination with the GP at 25 or 32 weeks of gestation. Pregnant women in their 2nd or 3rd trimester who attended the week 32 pregnancy examination before the offer came into force on 1 August 2023 may be offered vaccination at another visit, but they themselves need to schedule such a visit with their GP. Vaccination may be given until one week before delivery is expected.

Furthermore, the Danish Health Authority recommends that pregnant women with multiple pregnancy and other childbearing women at risk of giving birth prematurely discuss vaccination with their GP or the midwife at the department of obstetrics where they are being monitored. In this group, vaccination may also be offered before reaching the full 25 weeks of gestation, provided medical assessment warrants that birth is not expected within one week. However, vaccination may not be offered earlier than at 16 full weeks of gestation. The offer of vaccination to pregnant women in this group may be given as part of in-hospital treatment.

For more information, please see the Danish Ministry of Health’s Executive Order no. 1059 of 27/7/2023 (in Danish) and the Danish Health Authority’s Guideline no. 9602 of 27/7/2023 (in Danish) on free vaccination against certain infectious conditions, etc.

Vaccines

For use in the temporary vaccination programme, the SSI has purchased two trivalent whooping cough-containing vaccines, both of which have registered indication for pregnant women.

Triaxis from the manufacturer Sanofi contains a total of four whooping cough antigens. The vaccine contains aluminum phosphate and traces of formaldehyde and glutaraldehyde. A 0.5 ml dose is given intramuscularly, normally in the deltoid muscle.

The most frequent side effects in adults are headache, diarrhoea, myalgia and fatigue.

In various studies adopting different methodologies, the vaccine was shown to have a vaccine effectiveness of 91.4-93% at 2 or 3 months of age.

For additional information, please see the SSI’s Vaccine Encyclopaedia (in Danish).

Boostrix from the manufacturer GSK contains a total of three whooping cough antigens. The vaccine contains aluminum hydroxide/phosphate and may contain traces of formaldehyde. A 0.5 ml dose is given intramuscularly, normally in the deltoid muscle.

The most frequent side effects in adults are headache, redness/swelling/soreness at the injection site and fatigue.

In various studies adopting different methodologies, the vaccine was shown to have a vaccine effectiveness of 69.9-90.9% at 3 months of age.

For additional information, please see the SSI’s Vaccine Encyclopaedia (in Danish).

The vaccines also protect against diphtheria and tetanus, and it is assessed that the vaccines may be used even in cases of recent booster vaccination against these two conditions. Even so, a minimum of 4 weeks should pass from the latest diTe booster vaccination due to the risk of a strong local reaction at the injection site. If a diTe booster vaccination or a diTe-containing vaccine has been given within the preceding 12 months, the risk remains of a local reaction at the injection site.

Triaxis and Boostrix are given intramuscularly in the deltoid muscle and may be given concurrently with an influenza vaccine, but on opposite sides. Overall, the vaccines are considered equally effective.

As none of the vaccines have previously been used in a Danish vaccination programme, they are subject to enhanced monitoring by the Danish Medicines Agency. This means that doctors and midwifes have a duty to report all presumed side effects of the vaccine in pregnant women as well as in their children. All presumed side effects includes known side effects.

If the side effects are serious, they must be reported to the Danish Medicines Agency no later than 15 days after the symptoms presented.

It is important to remember that reporting is to be made based exclusively on the basis of a presumption of a connection between the symptoms and the vaccine. Presumed side effects may be reported electronically at meldenbivirkning.dk (in Danish).

How to order

Triaxis and Boostrix may be ordered via the web shop and, for use in the temporary vaccination scheme, they are available in 1-piece packings with French and German language packaging.

The 1-piece Triaxis packs have issue number 105524.

The 1-piece Boostrix packs have issue number 105526.

The manufacturer of Boostrix has applied for and the Danish Medicines Agency has granted an exemption from the Executive Order on Labelling. Therefore, only this vaccine may be ordered as from the initiation of the programme on 1 August. We expect that the manufacturer of Triaxis will also apply for and achieve this exemption, after which this vaccine will also become available via the web shop.

To ensure an adequate supply and avoid wasting vaccines, healthcare workers are recommended ordering only the number of vaccines currently needed. It will be possible to order the vaccine throughout the entire period.

Settlement and notification

The Danish General Practitioners’ Organisation (PLO) and the Regional Board for Wages and Tariffs (RLTN) have made an amendment to the Prophylaxis Agreement on whooping cough for pregnant women. This means that the previously used service has been re-activated:
Service 8803: whooping cough vaccination for pregnant women.

When pregnant women are vaccinated at their 2nd medical examination (at approx 25 full weeks of gestation), service 8120 + service 8803 (whooping cough vaccination) are used.

When pregnant women are vaccinated at their 3rd medical examination (at approx 32 full weeks of gestation), service 8130 + service 8803 (whooping cough vaccination) are used.

When pregnant women are vaccinated independently of the 2nd of 3rd medical examination or visit (0101), service 8803 (whooping cough vaccination) + service 8901 (additional vaccination fee) is used.

Monitoring of the coverage of the temporary vaccination programme is based on the statutory notification of vaccinations to the Danish Vaccination Register (DVR) through www.fmk-online.dk or via integration of the DVR into the electronic health record system used.

(P.H. Andersen, T. Dalby, J. Grau, Department of Infectious Disease Epidemiology and Prevention)
1 August 2023