Varicella vaccination schedule

Vaccines are not only to keep children away from diseases, but also to directly improve children's

Varicella vaccine is prepared by passaged strains of varicella virus and is the only means of preventing varicella infection. Getting the varicella vaccine not only prevents chickenpox, but also prevents complications caused by varicella-zoster.

Varicella-zoster virus (VZV) belongs to the herpesvirus genus A, herpesviridae family, and has 6 to 8 viral glycoproteins (G), which are associated with infection, production of neutralizing antibodies, viral replication and virulence. VZV has only one serotype, and it is still unclear whether there is cross immunity with other herpes viruses. Humans are the only host of this virus.

Starting from August 1, 2018, varicella vaccine was included in Shanghai's immunization plan. Anyone of appropriate age who was born on or after August 1, 2014 and resides in Shanghai, including non-Shanghai residents who have lived in Shanghai for three months or more, can receive the varicella vaccine free of charge.

Chickenpox is an acute, highly contagious infectious disease caused by the varicella-zoster virus. The main clinical symptoms are fever, and the appearance of macules, papules, vesicles and scabs in batches. In severe cases, it can even lead to death. Vaccination against varicella is the safest and most effective way to prevent varicella.

VZV mainly enters the respiratory lymph nodes through droplets and replicates, producing the first viremia after 4 to 10 days. The virus then spreads through the lymph and blood and is phagocytosed by monocytes. After 4 to 6 days, the second viremia begins. The virus is released in large quantities into the blood, enters the epidermis through the capillaries, invades the skin and forms vesicles. Chickenpox occurs when the body lacks immunity after primary infection with VZV. And it has the ability to continue to penetrate into the human body.

Herpes zoster is only seen in people who are infected with VZV and have had chickenpox. Although the pathogenesis is still unclear, it is believed that herpes zoster is the result of the virus lurking in the body after primary infection with VZV. When the body is in a certain pathological state and the defense function drops to a certain level, VZV revives and replicates in the nerve ganglion, and transmits retrogradely along the sensory nerves to the skin area innervated by the nerve endings and is released, producing a characteristic unilateral blister rash called herpes zoster.

Chickenpox is an infectious disease characterized by skin rash that occurs frequently in spring and autumn, with more than 90% of cases occurring among children. The main transmission routes are air droplets, direct contact and vertical transmission from mother to child. It can also be transmitted through contaminated utensils. It is easy to cause multiple outbreaks or outbreaks in childcare institutions.