Pneumococcal disease

Pneumococci are the commonest cause of community-acquired pneumonia – and at the same time one of the organisms against which pregnant women are expressly vaccinated in certain situations. This page explains what the organism does, why there are two completely different kinds of vaccine and when vaccination becomes an issue for women themselves.

What pneumococci are

Streptococcus pneumoniae is a bacterium that colonises the nose and throat of many healthy people. Among small children in day care, more than half carry it at times without being ill. This colonisation is the normal case; illness is the exception.

What is decisive is the sugar capsule surrounding the bacterium. It protects it from the scavenger cells of the immune defences and is at the same time the feature by which more than ninety different serotypes are distinguished. Only some of them cause most serious illness – and it is precisely at these that the vaccines are aimed.

The capsule also explains why people without a spleen are particularly at risk: the spleen filters encapsulated bacteria out of the blood, and without it this filter is missing. For this group the pneumococcal vaccination is therefore not one recommendation among several but one of the most important measures of all.

What pneumococci cause

The illnesses are divided into two groups. The common, mostly not life-threatening ones arise when the organism spreads from the nose into neighbouring areas: middle ear infection, sinusitis, bronchitis.

The second group is called invasive pneumococcal disease. It arises when the organism penetrates normally sterile areas – the blood, the cerebrospinal fluid, the lungs.

Pneumonia is the commonest serious form. Typical are a sudden high fever with shivering, a cough with rust-brown sputum, pain in the chest on breathing and breathlessness. In older people these signs are often absent; there pneumonia shows itself as confusion, a fall or a simple deterioration in general condition.

Blood poisoning and meningitis are rarer and more dangerous. Pneumococcal meningitis has the highest mortality among bacterial forms of meningitis and leaves lasting damage in a considerable proportion of survivors – most commonly hearing loss.

Two age groups above all are affected: children under two and people over sixty. Between them lies a long stretch with a low risk – interrupted by situations in which it rises.

When pneumococci become an issue for women

For healthy women of childbearing age a pneumococcal vaccination is not routinely provided for. But there are several situations in which it is recommended – and some of them come up in the gynaecological consultation.

• Chronic illnesses: asthma, COPD, heart disease, diabetes, kidney and liver disease.
• A missing or non-functioning spleen – here with particular emphasis and lifelong.
• Immune deficiency, congenital or acquired, including ongoing immunosuppressive treatment.
• Smoking – an often overlooked risk factor that markedly increases the risk of invasive disease.
• Cochlear implants and states following certain operations on the skull.

Anyone planning a pregnancy who meets one of these conditions should deal with the vaccination beforehand – not because it would be impossible in pregnancy, but because fewer questions have to be settled before it.

Pneumococci in pregnancy

Pregnancy itself is not an indication for pneumococcal vaccination in Austria. It does, however, change the course of a pneumonia, and that deserves putting in context.

Two circumstances come together. The immune defences are shifted towards tolerance in pregnancy – a necessity so that the child is not rejected, but at the same time a weakening against certain organisms. And towards the end the chest has less room to move: the uterus pushes the diaphragm upwards and the reserve for breathing falls.

As a result, pneumonia in pregnant women more often runs a severe course, and it is associated with an increased risk of preterm birth and low birth weight. Treatment is given consistently; penicillins and cephalosporins can be used well in pregnancy, and a chest X-ray where pneumonia is suspected is no reason for hesitation – see X-rays and radiation.

Where one of the conditions listed above exists and the vaccination was not dealt with before the pregnancy, it is possible during it as well: both kinds of vaccine are inactivated vaccines. The decision is taken case by case, because the data on use in pregnancy are limited – not because any harm is known.

Another connection, by contrast, is unambiguous: the influenza vaccination is recommended to every pregnant woman, in every trimester. A considerable proportion of severe pneumonia following influenza is caused by pneumococci settling on the virus-damaged mucous membrane. Anyone who has the flu vaccination thereby also prevents some pneumococcal disease.

Why there are two kinds of vaccine

This difference is often overlooked and is the key to understanding all the recommendations.

Polysaccharide vaccines contain the pure capsular sugars of 23 serotypes. They thus cover a great deal. Their disadvantage is fundamental: pure sugar structures produce an immune response without memory, they work practically not at all in children under two, and they do not prevent colonisation of the throat. Protection wears off after a few years.

Conjugate vaccines couple the capsular sugars to a carrier protein. This brings the sugar into the recognition pathway that works in infants too and leaves a memory behind. They cover fewer serotypes but work better, for longer and in the youngest as well – and they prevent colonisation, which produces a herd effect. The principle comes from the Hib vaccination.

Today's recommendations therefore prefer conjugate vaccines, in part followed by a polysaccharide vaccine in order to widen coverage. Which combination applies changes with the availability of newer preparations and is set out in the Austrian immunisation schedule currently in force. The individual preparations are described on the pages Prevenar 13 and Synflorix.

The immunisation schedule for children

In Austria the pneumococcal conjugate vaccination is included in the free childhood immunisation programme. It is given in the third and fifth month of life and between the twelfth and the fourteenth – that is, at the same appointments as the six-in-one vaccination, into the other thigh.

For premature babies and for children at increased risk a schedule with an additional dose is used, because in them the response to two doses is less reliable. Here too what applies to all vaccinations of the first year of life applies: the calculation follows actual age, not the calculated due date.

The success is well documented: since the introduction of conjugate vaccination, invasive pneumococcal disease in small children has fallen sharply in Europe. Because of the herd effect the frequency fell in adults and older people as well, who were not vaccinated at all – an effect that had not been expected on this scale when it was introduced.

Serotype replacement: the uncomfortable side

A vaccine that covers some of the serotypes creates a gap that other serotypes can fill. That is exactly what happened: after the introduction of the first conjugate vaccines the covered types decreased sharply, while individual uncovered ones became commoner.

This serotype replacement has not cancelled out the benefit of the vaccination – the total number of invasive infections has fallen markedly. But it is the reason why the vaccines are continually extended: from seven to ten and thirteen serotypes, and now to fifteen and twenty.

For parents and patients this has a practical consequence: which vaccine is currently used changes more often than with other vaccinations. The question “is this still the same one as with our first child?” is legitimate and is answered at the vaccination appointment.

Pneumonia in pregnancy: what you should know

Because this section establishes the practically most important connection between pneumococci and gynaecology, here it is in more detail.

The warning signs do not differ fundamentally from those outside pregnancy: high fever with shivering, cough, pain in the chest on breathing, breathlessness. What differs is how they are interpreted – because shortness of breath is common in pregnancy anyway, and it is precisely that which leads to a beginning pneumonia being attributed to the pregnancy at first.

The useful distinction is this: shortness of breath while climbing stairs that settles within minutes at rest belongs to pregnancy. Breathlessness at rest, breathlessness on lying flat, breathlessness with fever or chest pain does not – and should be assessed the same day.

In the investigation there is no hesitation. A chest X-ray involves about 0.05 millisieverts and is thus far below any threshold at which a risk to the child would be demonstrable; the unrecognised illness weighs orders of magnitude more heavily. Blood count and inflammatory markers are added.

Treatment is with antibiotics that are well studied in pregnancy – penicillins and cephalosporins in the first place. What is avoided in pregnancy are individual classes of substances such as tetracyclines and fluoroquinolones; the choice is made by the treating service, and it is wide enough.

A word about follow-up: a pneumonia that has been overcome in pregnancy is no reason to manage the rest of the pregnancy differently, but it is a reason to keep an eye on the child's growth on ultrasound – severe febrile illnesses can have an effect on it.

The influenza vaccination as part of the same consideration

Because it only appeared briefly above: the influenza vaccination is recommended in Austria to every pregnant woman, regardless of the trimester, and it is included in the free vaccination programme for pregnant women.

It protects twice over. Pregnant women fall more severely ill with influenza than other adults – for the same reasons given above for pneumonia – and are admitted to hospital more often. And the infant cannot be vaccinated itself in the first six months of life but falls particularly severely ill; it benefits from the antibodies that cross the placenta.

Secondary bacterial infection after influenza is the point at which the two subjects of this page touch. The influenza virus damages the mucous membrane of the airways; pneumococci, which are present in the throat anyway, thereby find a way downwards. A considerable proportion of the severe pneumonias in a flu season arise this way.

An inactivated vaccine is used. The vaccination can be given together with the dTpa vaccination, into different arms; see whooping cough.

Tolerability

The commonest reactions are local: redness, swelling and tenderness at the injection site for one to two days. In infants, fever, restlessness, loss of appetite and increased sleeping are added.

If the pneumococcal and the six-in-one vaccinations are given on the same day, fever is somewhat commoner than with separate appointments. This is known and accepted, because separate appointments mean more strain overall – and because fever after a vaccination is an intended reaction and not an illness.

In adults the conjugate vaccine is usually better tolerated than the polysaccharide vaccine, which can cause more pronounced local reactions, particularly on repeated administration. That is why the polysaccharide vaccine is not repeated at will.

What happens if someone falls ill

Treatment is with antibiotics, in Europe usually penicillin or amoxicillin, in severe cases intravenously and in hospital. The sensitivity of the organisms is still good in Austria; in some countries resistance is a considerable problem.

With invasive disease the organism is cultured from blood or cerebrospinal fluid and the serotype determined – not for treatment but for surveillance: only in this way can it be followed which types are circulating and whether the vaccines still fit.

Invasive pneumococcal disease is notifiable in Austria. Preventive treatment of contacts is – unlike with meningococci – not provided for, because colonisation is so widespread that it would offer no sensible starting point. You would have to treat a considerable part of the population in order to prevent a single case.

Middle ear infection: the commonest point of contact

For most families pneumococci are present not as the cause of severe illness but as one of several causes of middle ear infection – the commonest illness of early childhood at all.

It arises because in small children the Eustachian tube is short and runs horizontally. Organisms from the nose and throat thereby reach the middle ear more easily, especially when the mucous membrane is swollen from a cold anyway. As the child grows the tube becomes more upright and the problem disappears by itself – most children have hardly any middle ear infections after their sixth birthday.

The conjugate vaccination markedly reduces the number of middle ear infections caused by the covered serotypes, but the total number only moderately – because other organisms fill the gap. That is an honest qualification which belongs on the table before vaccination: it prevents severe invasive disease very well and earache only in part.

What actually helps with a middle ear infection has changed over the last two decades. In children over two without severe symptoms the approach today is first to wait and to treat the pain adequately; a considerable proportion resolve without an antibiotic. In infants, where both ears are affected, with high fever and with marked symptoms, treatment is given.

What happens next

The child's vaccinations are given by the paediatrician. In this practice the subject is relevant where one of the conditions named above applies – above all with asthma, diabetes, immune deficiency or a missing spleen, and where a pregnancy is planned. Please bring your vaccination record. Arranging an appointment.

It makes sense to go through all vaccinations together once anyway in preconception advice. There are more of them than you would think: rubella protection, which absolutely has to be in place beforehand, measles and chickenpox protection for the same reason, the HPV vaccination if it is still within the free programme, the basic course against tick-borne encephalitis with its long lead time – and, where the history calls for it, pneumococci. An appointment for this is time well spent, because afterwards only what belongs there anyway is left for the pregnancy: dTpa and influenza.