Hexyon – the six-in-one vaccine

Hexyon is one of the six-in-one vaccines used in Austria for the basic course of immunisation in the first year of life. For expectant mothers it is of interest for one particular reason: it only protects from the third month of life onwards, and the weeks before that are bridged by a vaccination in pregnancy. This page explains both – what is in the injection and how the gap before it is closed.

What Hexyon is

Hexyon is a combination vaccine against six illnesses. In infants it is injected into the thigh muscle and is part of the free childhood immunisation programme. Besides Hexyon there are other six-in-one vaccines which differ slightly in composition and are used as equivalents; which one is used is decided by the paediatrician according to availability.

It is an inactivated vaccine. It contains no organisms capable of multiplying but purified components – detoxified poisons, individual proteins from bacterial surfaces and killed viruses. This composition explains why several boosters are needed: an inactivated vaccine does not produce lifelong protection with a single dose.

The six components

Each of these illnesses has a page of its own – diphtheria, tetanus, whooping cough, polio, Haemophilus influenzae b and hepatitis B.

Why six in one injection

The commonest objection to combination vaccines is that six at once are too much for an infant's immune system. This concern is understandable and can be answered with figures.

A six-in-one vaccine today contains fewer than forty individual protein components in total. The smallpox vaccine of the 1960s contained around two hundred on its own. At the same time an infant encounters thousands of foreign substances day after day – through the skin, the air it breathes, its food and the bacteria colonising its gut. The load from a six-in-one vaccination disappears within that.

What actually speaks for the combination is practical: fewer injections, fewer appointments, fewer opportunities to forget a dose. If the six components had to be given separately, there would be eighteen appointments instead of three – and in practice immunisation programmes fail not on effectiveness but on missed appointments.

Single vaccines for all six components are in any case no longer on the market in Europe. The question of splitting them therefore no longer arises as a choice.

The schedule: two plus one

In Austria vaccination follows the so-called 2+1 schedule: two doses two months apart, then a third after a longer interval.

The third dose is the decisive one for the duration of protection. It must not be omitted, even though protection already exists after the first two – without the third dose it lasts only briefly. The longer interval before it is not a concession to scheduling but intended: a booster given late produces a stronger and longer-lasting response than one given early.

If an appointment is missed, the series is continued and not begun again. With this vaccine there is no deadline after which everything would have to be repeated. Every dose given counts.

The gap before it – and how pregnancy closes it

Here lies the gynaecological part of the subject, and it is the most important part of this page.

The first dose is given in the third month of life. Reliable protection exists only after the second, that is, at the earliest at around six months. In the weeks before that a child depends on what it received from its mother.

For whooping cough this gap is the most dangerous. Infants under three months fall ill most severely, often with pauses in breathing rather than with coughing. That is exactly why every pregnant woman in Austria is recommended a dTpa vaccination between weeks 27 and 36: the antibodies formed cross the placenta to the child in the last third of pregnancy and carry it through until its own vaccination. More on this on the page whooping cough.

For hepatitis B a different mechanism applies. If the mother is HBsAg-positive – which is checked in weeks 24 to 28 in the parent-child pass – the newborn is given antibodies and a first dose of vaccine within twelve hours of the birth. This simultaneous immunisation prevents transmission in more than ninety per cent of cases; see hepatitis B.

For tetanus and diphtheria a vaccinated mother likewise transfers antibodies. Worldwide this is of considerable importance: tetanus of the newborn remains a common cause of death in countries without immunisation programmes.

The pattern behind this is worth noting: two of the six components of the six-in-one vaccine have a counterpart in antenatal care. What happens in the practice, and what happens six months later at the paediatrician, belong together.

What is normal after the vaccination

The commonest reactions appear in the first one to two days and are an expression of the immune system doing its work:

• redness, swelling and tenderness on the thigh
• fever, usually below 39 degrees
• restlessness, more crying, poorer sleep
• loss of appetite for a day
• tiredness and increased sleeping

These reactions subside within one to two days. Cooling the injection site helps, as does an antipyretic in a dose appropriate to the age if the child is suffering. Lowering fever preventively is not recommended – it damps down the response to the vaccination slightly without any benefit arising.

What belongs with a doctor: fever above 39.5 degrees, fever lasting more than 48 hours, a seizure, unusually shrill crying over hours, marked swelling of the whole leg or striking listlessness.

How a vaccination appointment can be made more bearable

This is not a medical side issue. How a child experiences its first vaccination appointments influences how it experiences later ones – and how the parents experience them. Some of it can be influenced.

Breastfeeding or a bottle during or immediately after the injection measurably reduces the pain response. This has been shown in several studies and works better than anything else parents can do. Where breastfeeding is not possible, a small amount of sugar solution on the dummy helps.

Hold the child upright rather than laying it down. An infant in its mother's arms, skin to skin, cries for a shorter time than one on the examination couch.

Do not announce it in advance and do not comfort before anything has happened. In older children a long preparation increases the tension. Staying calm achieves more than any explanation – children read their parents' mood more reliably than their words.

Several vaccinations at one appointment are overall less of a burden for the child than ones spread over several appointments. The stress arises from the situation, not from the number of injections.

After the vaccination it is usual to wait a quarter of an hour at the practice. That is purely a precaution: very rare immediate reactions occur during this time, and practically not afterwards.

What a six-in-one vaccine does not contain

Three components are regularly mentioned which do not occur in the vaccines used today, or not in any relevant form.

Mercury. Thiomersal, a mercury-containing compound, used to be employed as a preservative in multi-dose containers. Today's vaccines for infants in Europe are single doses and do not contain it. The discussion about it dates from the 1990s and is beside the point for current vaccines.

Formaldehyde. It is used in manufacture to render toxins harmless and is largely removed afterwards. What remains in traces is far below the amount the human body forms in its own metabolism anyway – formaldehyde is a normal intermediate product of our own metabolism.

Live organisms. A six-in-one vaccine cannot cause any of the six illnesses, because it contains no organisms capable of multiplying. Fever after the vaccination is a reaction of the immune system to the components, not an attenuated form of the illness.

The illnesses nobody sees any more

One circumstance makes advising about these vaccinations more difficult than about many others: hardly anyone has ever seen one of the six illnesses. A decision about vaccination is thus taken between a concrete, visible small drawback – a crying child, a day with fever – and an abstract, invisible large benefit.

Psychologically that is an unfavourable starting position, and it explains why vaccination rates fall as soon as an illness has become rare. Historically this can be traced several times: in several countries public debates about vaccination were followed by a fall in participation – and a few years later by the reappearance of illnesses that had been thought gone.

The best way of dealing with this is not exhortation but precision: concrete figures on the benefit, concrete figures on the side effects, and an honest account wherever something is not known for certain. These pages are written in that spirit.

Aluminium in the vaccine

Six-in-one vaccines contain aluminium salts as an adjuvant. They ensure that the immune system reacts to the purified components at all – without them, considerably more antigen and more doses would be needed.

To put the quantity in context: one dose of vaccine contains less than one milligram of aluminium. In the first six months of life an infant takes in a multiple of that through food – breast milk and infant formula contain aluminium just as drinking water and practically all foods do, because it is one of the commonest elements in the earth's crust.

Studies of the aluminium load from vaccinations agree in concluding that it is small compared with daily intake through food. No connection with neurological illness could be found in large studies.

Premature babies

Premature babies are vaccinated according to their actual age, not their corrected age. A child born two months early therefore also gets its first dose in the third month of life.

That is not an oversight but deliberate: it is precisely children born too early who received fewer maternal antibodies – the transfer takes place above all in the last third of pregnancy – and who fall ill more severely. They need their own protection earlier, not later.

In very immature premature babies the first vaccination is occasionally given as an inpatient, because brief pauses in breathing can occur afterwards. That is a precaution and not a reason to postpone the vaccination.

How the vaccination record is kept

Every vaccination is entered with the date, the trade name and the batch number – in the yellow vaccination record, in the parent-child pass or, for some time now, in the electronic vaccination record that is part of the electronic health file. The electronic entry has the considerable advantage that it cannot get lost.

This sounds like administration and is not. A missing vaccination record is the commonest reason why people are later vaccinated unnecessarily or have to research laboriously – on starting school, in a pregnancy, before travelling, after an injury. Any adult who has looked for her own vaccination record knows what this is about.

A practical piece of advice from the consulting room: photograph your child's vaccination record after every appointment. It takes ten seconds and, if it is lost, replaces the entire search. The same applies to your own record – it will be needed before a pregnancy at the latest.

When it is postponed

It is postponed with an acute febrile illness – not because of a risk but because the reaction to the vaccination and the signs of the illness could otherwise not be told apart. A cold without fever, a slight cough or a course of antibiotics under way are not reasons to postpone.

The vaccination is not given where there has been a documented severe allergic reaction to one of its components, and with a severe neurological illness that has not yet been investigated – here the cause is clarified first.

Not reasons to postpone, by contrast, are: a chronic illness in a stable state, an allergy to foods or pollen, atopic eczema, asthma, a preterm birth, low weight, a forthcoming operation or the fact that siblings are ill at the moment. This list is here because in practice it regularly leads to unnecessary postponements – and every postponement lengthens the time during which a child is unprotected.

What comes afterwards

After the basic course a booster follows at primary school age, usually with a four-in-one vaccine against diphtheria, tetanus, whooping cough and polio. After that, boosters are given in adulthood every ten years, and from 60 every five.

For women this last sentence is not incidental. The dTpa booster is exactly the vaccination that becomes due again in a pregnancy – and the question about the last booster is asked in antenatal care. Anyone who has the vaccination record to hand saves time at this point.

The hepatitis B component occupies a special position here: after a complete basic course it needs no routine booster, because protection lasts a very long time in people with a healthy immune system. The same applies to Haemophilus influenzae b, whose illnesses hardly occur beyond early childhood – here the need for vaccination simply ends with the age at which the illness is dangerous.

What happens next

The child's vaccinations are given by the paediatrician. In this practice it is the part before that which matters: the dTpa vaccination in pregnancy, the hepatitis B test, rubella protection and the question of what has to be caught up after the birth. Arranging an appointment.