It is becoming increasingly evident that vaccines will be necessary in controlling the Covid-19 pandemic. Early evidence suggests that immunity to the SARS-Cov2 virus starts declining after 2 months, especially in the elderly. It is not yet clear when it declines sufficiently that reinfection could occur. Second issue is that not all infected develop strong antibodies and those that are asymptomatic after an infection develop antibodies that are at much lower titers than those that have suffered a severe infection.
Gene sequencing to identify reasons for increased susceptibility in some individuals is currently under way. For vaccines to work, they have to produce durable and elevated neutralizing antibodies that prevent the virus from entering the cells. These vaccines trigger creating antibodies that will block the ACE2 receptor or bind to the spike protein of the virus thus blocking the interaction between the receptor and the virus spike protein or the binding domain. It is becoming obvious from the initial results of the MRNA vaccine, BNTX vaccine and Astra Zeneca vaccine that two doses will be necessary, perhaps even three. The World may need about 7 billion vaccines at the outset given need for two doses. It is also possible that the vaccination may need to be done every 6 months to a year apart just like the flu vaccine.
The dominant players are Moderna, Pfizer BioNtech, Astra Zeneca, Johnson and Johnson, Novavax, and some others. Novavax will be announcing their phase I read out of 130 patients in the first week of August. The Chinese companies are ahead of others in their trials. One of the concerns coming out from the phase I trials is that the majority of them have fevers or malaise and pain. No other serious adverse effects have been noticed yet. Please wear masks in public and Stay Safe.