Do Chickenpox Cases Increase In Spring?
Chickenpox is a very common disease that occurs especially in young children. For this reason, many parents are aware of minors in times like winter and spring, where cases of this disease seem to increase. Why do chickenpox cases increase in spring?
The dynamics of the spread of chickenpox may seem counterintuitive, since, with the exception of allergy and some other pathology, most seasonal diseases usually show peaks in autumn and winter.
Chickenpox facts
Before knowing why chickenpox cases tend to increase during the spring, it is necessary to know a little about the cause of this annoying disease. Let’s see more information about it below.
- Chickenpox is a disease caused by the varicella-zoster virus. This pathogen has a double-stranded DNA molecule and is genetically related to the herpes simplex virus.
- According to the Community of Madrid health portal , chickenpox is a classic childhood disease, and unless they are vaccinated, almost all children go through it before adolescence.
- This virus is transmitted only from person to person, either by direct contact with the skin rashes it causes or by coughing and sneezing. It is quite contagious, and it has been detected that 80 to 90% of those who share a routine with a patient can get it.
- The characteristic symptom of this pathology is the appearance of blisters all over the body, which tend to be very itchy.
Once the causative virus is known, we are going to delve into a scientific article that tries to elucidate the relationship between the spread of chickenpox with changes in temperature.
The effect of temperature on chickenpox
In 2012 an interesting study was published in the medical journal Journal of the American Academy of Dermatology regarding the subject in question.
- In a hospital in China , the number of daily visits by patients with chickenpox and herpes-zoster between 2008 and 2010. A total of 3,520 patients with chickenpox and 6614 with herpes-zoster were recorded.
- On a daily basis, from a meteorological station near the hospital, climatic variables were collected, such as maximum and minimum temperatures, average temperature and average humidity.
- Statistical models were used to predict the relationship between both variables (number of infections and the weather).
The results are, to say the least, counterintuitive. It was observed that, for each degree increased in the mean temperature, the number of patients with chickenpox decreased by 1.33%, but those with herpes zoster increased by 2.18%.
The relationships between both parameters are very complex, since both diseases are related. After all, shingles is a reactivation of the chickenpox virus.
Chickenpox and spring: possible explanations
These results can be very confusing. Chickenpox has been observed to be seasonal and in many places has shown high peaks during the spring. Therefore, the fact that its incidence decreases with increasing temperature is the least strange. Even so, there are certain reservations to take into account in the face of the present study. We detail them below.
- The incubation period for chickenpox is 10 to 21 days. The transmission mechanism may be at peak levels in late winter, but symptoms do not begin to appear until well into the first spring month.
- The study was carried out in a single hospital, so the results should not be taken as fixed reality.
- Other research suggests that the transmission dynamics of shingles and chickenpox may be affected by vaccination schedules.
The incidence of shingles and temperature
Still, the research team tries to clarify why shingles did show a positive correlation with increased temperature. In this regard, the following was determined:
- Herpes-zoster remains latent after expression in the form of chickenpox in the patient’s body. The immune system can be affected by sudden changes in temperature, thus lowering its effectiveness. This diminished efficacy could give the virus a chance to reactivate during the spring.
- The combination of high temperatures and the incidence of ultraviolet rays from the sun could induce the suppression of immunity at the cellular level. This makes it easier for the virus to express itself.
The clearest answer to the proposed question is that it is not entirely clear why chickenpox shows certain peaks in spring.
Although it seems that the increase in temperature reduces its transmission, dynamics with the reactivation of herpes-zoster, vaccination schedules and changes in human habits can greatly alter this epidemiological picture.
