Coronavirus (Covid-19) infection and death rate has increased in the country in the last few days. The International Diarrhea Research Center Bangladesh (ICDDRB) has blamed two new sub-variants (BA4 and BA5) of the Omicron variant for the rapid spread of the infection. Although these sub-variants are highly contagious, the death and hospitalization rates are low, the research center said. This information was given in the report published on the official site of ICDDRB on Tuesday (July 5). It is said that BA4 and BA5 are spreading faster than the previous sub variants. This has led to a new wave of infections in the country. The two sub-variants were first identified in South Africa in January and February this year. On December 6, the first Omicron variant was identified in the country. In the first two weeks of January this year, most of the corona positive cases were BA1. Later, the sub variant BA2 was infected from the third week of January. Over time, BA1 is replaced by infection until the first week of April. According to the ICDDRB, sequencing was not possible between April 9 and May 13 due to very low corona detection rates in the country. In this situation, the first suspected Omicron subversive BA5 patient was identified on May 19 in Dhaka. Then in the last six weeks (May 14 to June 24) BA.5 became the most influential subvariant. Even during this period, 51 BA5 subvariets and one BA2 were identified in 52 corona positive cases using full genome sequencing. Observing the clinical data and vaccination history of 40 BA5 infected patients, it can be seen that there are 18 males and 24 females among the infected. Of these, 39 had mild coronary heart disease and one had no symptoms. Only one of them had to be hospitalized. Eleven of them contracted corona for the second time and seven for the third time.