How to recognize complications after vaccination?

Complications after vaccination rarely occur in children in the first six months of their life, especially since they can be masked by other diseases of this age. However, it is tactically correct to think first about other types of pathology, only after excluding which one can raise the question of the connection with complications after vaccination. It is especially important to exclude meningitis, pneumonia and emergency surgical pathology, since delay in their treatment is life-threatening.

To resolve this issue, it is important to take into account the time of development of the disease.

"Complications after vaccination" - does not always mean - "from vaccination". Thus, an increase in temperature later than the 2nd day after vaccination with inactivated preparations or before the 5th or after the 15th day after the introduction of live vaccines, as a rule, is not associated with its implementation (after the introduction of LPV, meningitis develops before the 25th day, and orchitis - before the 42nd day). But even in cases of the appearance of temperature, rash at the specified time, their persistence for more than 2-3 days and / or the addition of new symptoms (vomiting, diarrhea, meningeal signs), makes their connection with its implementation unlikely. Such situations require hospitalization, while a thorough anamnesis should be collected, especially with regard to the child's contacts, sick people in the environment, contact with allergens.

There are no pathognomonic symptoms that would allow one to clearly consider the event of a complication after vaccination, so this is always a probabilistic statement even after excluding all other possible causes.

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Infectious diseases

ARI is most often mistaken for complications after vaccination, including after DPT, although catarrhal syndrome is not typical for complications of DPT.

Fever without visible source of infection (FVII) and without catarrhal symptoms in an infant carries a 10-15% risk of bacteremia with the risk of developing meningitis, pneumonia, etc. These symptoms are very similar to complications after vaccination. In the presence of leukocytosis above 15x10 ⁹ /l, neutrophilia above 10x10 ⁹ /l, CRP above 70 g/l - the administration of ceftriaxone is indicated (IV 80 mg/kg/day).

Urinary tract infection is a common cause of complications after vaccination, diagnosis is difficult if there is no dysuria. Urinalysis (preferably culture) is mandatory for fever of unknown genesis.

Enterovirus infection is a common cause of LBOI, sometimes with meningism and convulsions. It is easily recognized in the presence of herpangina, characterized by a maculopapular rash (ECHO exanthema) against the background of a decrease in temperature after 4-5 days.

Infection with herpes viruses types 6 and 7 also occurs with high fever. The rash (sudden exanthema) appears after 3-4 days, in the first days the diagnosis of complications after vaccination.

Acute pneumonia is mistaken for a “vaccination reaction” due to the paucity of physical symptoms with underestimation of general symptoms (febrile condition >3 days, dyspnea in the absence of bronchial obstruction); X-ray confirms the diagnosis of complications after vaccination.

Meningitis in the first 3-5 days after the administration of killed vaccines is often mistaken for post-vaccination encephalitis or encephalopathy. The appearance of convulsions, meningeal signs after vaccination, especially against the background of fever and repeated vomiting, requires immediate lumbar puncture to exclude meningitis. Purulent meningitis as a complication after vaccination is not typical; serous meningitis with a good prognosis rarely occurs after LPV (usually after 10-25 days).

Intestinal infections: diarrhea and other intestinal symptoms are not typical for vaccination pathology.

Among other bacterial infections in the post-vaccination period, it is necessary to mention tonsillitis and scarlet fever caused by hemolytic streptococcus.

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Non-communicable diseases

Febrile seizures often accompany an increase in temperature after DPT, live vaccines, however, they are not considered as complications after vaccination, and are prevented, especially in children prone to them, by administering antipyretics.

Spasmophilia against the background of active rickets with hypocalcemia can cause afebrile seizures, as complications after vaccination, especially in children aged 3-6 months in the spring. Spasmophilia can be suspected by the child's excess weight and the prevalence of cereals in his diet. An ECG gives an indication of hypocalcemia - a pointed isosceles T wave.

Epilepsy is a common cause of afebrile seizures as a complication after vaccination, which is established using EEG. Sometimes, with the 1st episode of seizures, in the absence of epilepsy in the family history and unclear EEG data, it is necessary to recognize the episode as a complication, and only observation allows us to make the correct diagnosis.

Brain tumor (astrocytoma, ependymoma) can also be the cause of neurological disorders after vaccination. A gradual increase in symptoms and signs of intracranial hypertension should be alarming.

Leukodystrophies - a group of hereditary diseases, genetically deciphered recently - can manifest at the age of 3-4 months. Their coincidence in time with the introduction of DPT and the similarity of their symptoms with encephalitis was, apparently, the basis for talking about post-vaccination encephalitis.

Traumatic injury of the sciatic nerve occurs with an injection into the buttock. Its symptoms (the child is restless, does not lean on the leg on the side of the injection) appear immediately, as complications after vaccination, which distinguishes them from neuritis (transient weakness of the limb with hyporeflexia), which occurs after a few days and is a consequence of a presumed enterovirus infection; they require differential diagnosis with VAP, patients should be examined according to the AFP program. Unlike VAP and poliomyelitis caused by the wild virus, these neuritis do not leave consequences when examined after 2 months.

Polyradiculoneuritis (Guillain-Barré syndrome) is considered a complication after DPT and influenza vaccination; however, its course is no different from the classic disease not associated with vaccination. Children who have had Guillain-Barré syndrome not associated with vaccination can be safely vaccinated (DPT + OPV) 6 months after recovery. All patients are examined according to the general practice program.

Thrombocytopenic purpura is often observed on the 3rd-4th day after the introduction of DPT and is considered a complication after vaccination; in its course and favorable outcome it does not differ from that in children of the same age who did not receive vaccine preparations, which confirms the presence of only a temporary association. Relapses are described with subsequent introduction of ZIV, which is evidence of its probable connection with measles vaccination.

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