Most people will escape “severe” side effects, defined as those that prevent daily activity. Fewer than 2% of recipients of the Pfizer and Moderna vaccines developed severe fevers of 39°C to 40°C. But if the companies win regulatory approvals, they’re aiming to supply vaccine to 35 million people worldwide by the end of December. If 2% experienced severe fever, that would be 700,000 people.
Other transient side effects would likely affect even more people. The independent board that conducted the interim analysis of Moderna’s huge trial found that severe side effects included fatigue in 9.7% of participants, muscle pain in 8.9%, joint pain in 5.2%, and headache in 4.5%. In the Pfizer/BioNTech vaccine trial, the numbers were lower: Severe side effects included fatigue (3.8%) and headache (2%).
But that’s a higher rate of severe reactions than people may be accustomed to. “This is higher reactogenicity than is ordinarily seen with most flu vaccines, even the high-dose ones,” says Arnold Monto, an epidemiologist at the University of Michigan School of Public Health.
The engines of the SARS-CoV-2 pandemic—household and residential settings, community, and long-distance transmission—have important implications for control. Moving from international to household scales, the burdens of interventions are shared by more people; there are few international travelers, but nearly everyone lives in households and communities. Measures to reduce household spread may appear particularly challenging, but because they directly affect so many, they need not be perfect. Household mask use and partitioning of home spaces, isolation or quarantine outside the home, and, in the future, household provision of preventive drugs could have large effects even if they offer only modest protection. Conversely, control measures at larger spatial scales (for example, interregional) must be widely implemented and highly effective to contain the virus. Indeed, few nations have managed to curb infection without stay-at-home orders and business closures, particularly after community transmission is prevalent.
Over long periods of time, social isolation can increase the risk of a variety of health problems, including heart disease, depression, dementia, and even death. A 2015 meta-analysis of the scientific literature by Julianne Holt-Lunstad, a research psychologist at Brigham Young University, and colleagues determined that chronic social isolation increases the risk of mortality by 29%.
A prominent pediatrician and medical researcher in the Philippines has been indicted over the failed—and many say premature—introduction of Dengvaxia, a vaccine against dengue that was yanked from the Philippine market in 2017 because of safety issues. If convicted of accusations leveled at her by the national Department of Justice (DOJ), Rose Capeding, 63, former head of the dengue department of the Research Institute for Tropical Medicine (RITM) here, could face up to 48 years in prison.
…Halstead’s concerns proved valid. In November 2017, Sanofi Pasteur announced that the vaccine could indeed exacerbate cases of dengue in children never previously infected, and the Philippines halted the campaign immediately. (WHO now recommends the vaccine be used only after a test to be sure children have had at least one brush with dengue.)
Exposure to microbes during early childhood is associated with protection from immune-mediated diseases such as inflammatory bowel disease (IBD) and asthma. Here, we show that in germ-free (GF) mice, invariant natural killer T (iNKT) cells accumulate in the colonic lamina propria and lung, resulting in increased morbidity in models of IBD and allergic asthma as compared with that of specific pathogen-free mice. This was associated with increased intestinal and pulmonary expression of the chemokine ligand CXCL16, which was associated with increased mucosal iNKT cells. Colonization of neonatal—but not adult—GF mice with a conventional microbiota protected the animals from mucosal iNKT accumulation and related pathology. These results indicate that age-sensitive contact with commensal microbes is critical for establishing mucosal iNKT cell tolerance to later environmental exposures.