A mix and match of the vaccines or heterologous dosing of different brands for first and second doses appears to give a good protection due to stronger immune response against the COVID-19 variants, as per the scientific research and studies done worldwide.
Many trials have been conducted on heterologous dosing, and it has shown that the response to the new variant is much higher when the different vaccines for COVID-19 are combined.
“So if this evidence were not there, the country would never go for this method,” said Dr Sonam Wangchuk, a member of the National Immunization Technical Advisory Group (NITAG).
Dr Sonam said a mix and match of vaccines are technically called heterologous and homologous is getting the same vaccine. The priority is given to the safety of the vaccine, then immunogenicity, how well the immunity is boosted or how well it is protected against the virus.
For any COVID-19 vaccine that has been rolled out in the world, the evidence shows that it is clearly safe.
Dr Sonam said a mix and match of vaccines is not new in the world. It has been tried a long time back. m-RNA virus keeps on mutating, so there are various variants. First dose is to build the immunity and as virus change, the antibody will try to drop and if its drop down below threshold level, then the booster dose might be given annually.
The emergence of new variants may continue for some time unless the vaccine coverage is 80-90 percent globally. The current vaccine is mostly of the first COVID-19 variant but now companies are working on other vaccines. So the way forward is that for some time, the booster doses will be required.
The news covered on heterologous vaccines are preliminary reports. Dr Sonam said a mix and match of vaccines gives good protection against the variant. However, this does not mean a person taking the same vaccine brand as the second dose will not get the protection against the variant.
The clinical trial for heterologous was conducted as early as in February, so from the immunity point of view, it is proven to be better. However, the study is still going, and whatever the findings are, many countries in the world have been rolling out such mix and match vaccines. Every study is pointing out that there is higher immunity in heterologous and no serious adverse reaction so far. Several European countries have adopted heterologous. Some countries who have completed homologues are considering a booster dose because of the new variant emerging.
NITAG recommends that heterologous is best and more antibodies are formed, and it has the better protection against the variant.
Health Minister Dasho Dechen Wangmo said people are concerned over a mix and match of vaccines. Health Minister said the ministry is going with it, not because there are not enough vaccines but purely based on efficacy. The studies have suggested that heterologous gives more protection. Otherwise Moderna vaccines can be saved and given to children later if people do not choose Moderna as their second dose.
Meanwhile, Dr GP Dhakal of NITAG said the side effect to the second dose of vaccine will not be as severe as what the people might have experienced while taking the first dose. NITAG also recommends taking paracetamol if anyone should experience any side effects. People who are alcoholic can drink a small controlled portion of alcohol, and NITAG does not recommend that they should completely stop drinking alcohol.
Dr Dhakal said as per the past experience, some patients, preparing themselves to take the vaccination, suffered stroke as they had stopped taking their medicines for diabetes and hypertension. However, there are some medicines that have to be stopped, and therefore, MoH has a list of patients who will be informed and asked to stop their medication to take the vaccine.