Almost every child has been infected with rotavirus before the age of 5, so please get vaccinated as early as possible!

According to statistics, almost all children have been infected with rotavirus before the age of 5. There are about 111 million to 135 million cases of rotavirus gastroenteritis worldwide each year, resulting in the death of 650,000 infants. In my country, about 18 million infants and young children suffer from rotavirus gastroenteritis each year, and nearly 40,000 children die from rotavirus gastroenteritis, accounting for about 12% of the total number of deaths in children under 5 years old in China. There are records of outbreaks of rotavirus gastroenteritis in all provinces and cities in my country, and they can occur throughout the year. The World Health Organization (WHO) believes that: except for vaccines, there is no effective way to completely eliminate rotavirus or its transmission. Vaccination with rotavirus vaccine is the most effective measure to prevent and control rotavirus gastroenteritis in children.

So, what rotavirus vaccines are available now? How to get vaccinated?

No specific cure yet

Rotavirus (RV) is a double-stranded RNA virus belonging to the Reoviridae family. Under an electron microscope, rotavirus particles look like wheels, so they are named rotavirus. The genome of rotavirus consists of 11 unique RNA double helix molecules, each helix or segment is a gene, and they are numbered 1 to 11 in order from large to small according to the size of the molecule. There are 7 species of rotavirus, numbered A, B, C, D, E, F and G in English letters. Among them, species A is the most common one, and more than 90% of human rotavirus infections are caused by this species.

There are different strains of rotavirus A, called serovariants. Similar to influenza virus, rotavirus uses a dual classification system, which uses a combination of P type and G type to label each strain of the virus. The most common serotype that causes rotavirus gastroenteritis is G1, followed by G2, G3, G4, G6, etc.

Rotavirus gastroenteritis mostly occurs in infants and young children aged 6 to 24 months. In addition to causing intestinal infection, diarrhea, dehydration, electrolyte imbalance, etc., the disease can also cause viremia, leading to more serious complications such as myocarditis, encephalitis, pneumonia, hepatitis or acute pancreatitis. However, there is currently no specific drug for rotavirus infection, and clinical treatment is mainly symptomatic for dehydration and electrolyte imbalance. Therefore, to effectively prevent rotavirus gastroenteritis, rotavirus vaccine should be administered as soon as possible.

Prevention through vaccines

There are currently two types of rotavirus vaccines on the market in China: oral rotavirus live vaccine and oral pentavalent reassortant rotavirus live attenuated vaccine (Vero cells).

The research and development of live rotavirus vaccines began in 1983. The main strategy is to adopt Jenner's vaccination method, which is the principle of "vaccinating cowpox to prevent human smallpox". Rotavirus can infect humans and many young animals, and has strict host specificity. Rotavirus from non-human hosts is non-toxic or weakly toxic to humans. Therefore, vaccination with animal rotavirus is safe for humans and can obtain effective immunity. At present, an oral live rotavirus vaccine on the market is made with sheep rotavirus as an immunogen. This vaccine has a single component, simple preparation, and low cost, and contains the main rotavirus serotype G1 that causes rotavirus gastroenteritis.

However, this vaccine also has disadvantages. First, it can generally only contain one strain of virus, one serotype. Second, the animal rotavirus genes used in the vaccine are different from those of humans, and its immune effect may be affected to a certain extent.

Therefore, scientists are committed to the research and development of oral rotavirus live vaccines with rotavirus gene reassortment strains. That is, based on the weak toxicity of the animal rotavirus genome, gene fragments of human rotavirus are inserted using gene reassortment technology to enhance the immune effect of the vaccine. For example, the human rotavirus G1, G2, G3 and G4 genes are respectively inserted into the genomes of four bovine rotaviruses to replace the original corresponding genes of the bovine rotavirus, forming four new reassortment viruses. Another reassortment virus of the vaccine uses human attenuated rotavirus as the parent, and its original G1 gene is replaced by the G6 gene of bovine rotavirus. Therefore, the oral pentavalent reassortment rotavirus attenuated live vaccine contains the most important serotypes G1, G2, G3, G4 and G6 that cause rotavirus diarrhea.

Both vaccines have been approved by the State Food and Drug Administration and are widely used in China, playing a major role in preventing rotavirus gastroenteritis in infants and young children.

At present, the oral rotavirus live vaccine available in my country is a domestically produced vaccine, and the vaccination age is 2 months to 3 years old; one dose is given every year; the first dose should be given as early as possible from 2 months of age.

The oral pentavalent reassortant rotavirus live attenuated vaccine is an imported vaccine. The vaccination age is 6 to 32 weeks, and the full immunization is 3 doses. The first dose is 6 to 12 weeks of age (42 to 90 days) after birth. The interval between each dose is ≥ 4 weeks; the third dose must not be later than 32 weeks of age (230 days). It is important to remind you that if one dose of the pentavalent vaccine is over the age limit, this dose and the remaining doses cannot be vaccinated. Parents must complete the vaccination within the time limit!

Author: Yaohuluwa Medical Biotechnology Science Popularization Group