Vaccines 2026

An executive order signed by U.S. President Donald Trump instructs health authorities to modify childhood immunization guidelines by separating the combined measles, mumps, and rubella (MMR) vaccine into three separate injections administered during distinct medical visits. The directive has drawn sharp criticism from medical associations, public health experts, and lawmakers, who argue that it directly contradicts established medical and scientific consensus.

The Brazilian Ministry of Health has announced a temporary suspension of its mass immunization campaign using the domestically produced Butantan-DV vaccine, pending an investigation into the deaths of two vaccine recipients. Brazilian health authorities have ordered a precautionary halt to the rollout of Butantan-DV, a newly developed single-dose dengue vaccine produced by the country's renowned Instituto Butantan in partnership with WuXi Vaccines. The decision follows reports of two suspected fatalities, a 58-year-old man and a 48-year-old woman, as well as a third recipient who required emergency admission to an intensive care unit. These severe adverse events occurred among approximately 500,000 individuals who have received the vaccine since its recent introduction.

A Belgian court has ruled in favor of Pfizer Inc., ordering Poland and Romania to pay a combined €1.9 billion for failing to meet their obligations under a large-scale COVID-19 vaccine procurement agreement. The ruling stems from a 2021 contract negotiated by the European Commission on behalf of EU member states. Under its terms, countries committed to purchasing a predetermined number of doses. As the public health crisis stabilized and vaccine demand declined, Poland and Romania halted deliveries and ceased payments, prompting Pfizer to initiate legal action in 2023.

The novel oral polio vaccine type 2 (nOPV2) was widely regarded as a major advance in global polio eradication efforts. The vaccine strain was engineered to enhance genetic stability and reduce the likelihood of reversion to neurovirulence. However, a recent study published in Nature Microbiology demonstrates that, under specific conditions, even these advanced safeguards can be circumvented through viral recombination. The study reports the isolation of a “double recombinant” poliovirus from environmental samples collected in Uganda. This variant originated from the nOPV2 vaccine strain but underwent two distinct genetic recombination events with other members of Enterovirus species C. As a result of this genetic reshuffling, the virus regained a neurovirulent phenotype.