Harvard Undergraduate Secondary

A secondary field provides the opportunity for a Harvard Undergraduate to pursue guided and recognized work in a field outside of the concentration.

To clarify the rules and regulations around secondary concentrations, please see this page of Student FAQ and this page of guidance from the university.

About the Secondary

MSI is proud to coordinate a secondary in Microbial Sciences for Harvard undergraduate students. Secondary fields provide the opportunity for focused study (four to six courses) outside of the primary area of concentration.

Microbial sciences is an interdisciplinary approach to studying the impact of microbes at scales from global ecosystems down to single-celled microenvironments. The academic program emphasizes the joint study of species diversity, metabolic function, geochemical impact, and medical and pharmaceutical applications of microbial sciences. Faculty affiliated with the Microbial Sciences Initiative (MSI) include members from Molecular and Cellular Biology, Organismic and Evolutionary Biology, Earth and Planetary Sciences, Chemistry and Chemical Biology, the School of Engineering and Applied Sciences, Harvard Medical School, Harvard School of Public Health, and the Forsyth Institute.

The MSI secondary field is intended to provide a strong foundation in interdisciplinary microbial sciences to students who have sufficient preparation in other natural sciences, mathematics, or engineering. In particular, the MSI curriculum is intended to (i) be interdisciplinary, (ii) not be specifically biomedical, and (iii) incorporate elements from physical sciences as well as life sciences. An important aspect of the MSI secondary field is the laboratory component, which provides hands-on experiential learning to all students.


  • Typically, with the exception of approved SAT/UNS Freshman Seminars, all courses must be taken for a letter grade in order to count toward secondary field credit, and under these conditions C is the minimum acceptable grade.
    • ***However, exeptions may also be made for COVID19-based academic disruptions on a case-by-case basis.***
  • Of the one introductory course and two additional microbial courses, two must be significantly outside the student's primary area of concentration, providing each student substantial interdisciplinary experience. Note that this aligns with the university-wide requirement that only one course may double-count for a student's concentration and secondary.
  • Some courses for Microbial Sciences credit may have hidden prerequisites. Students should plan appropriately, as a prerequisite cannot be counted for Microbial Sciences credit unless it satisfies requirement 2 above. 
  • Students may receive credit for Life Sciences 100r twice. Students electing to do this may count one semester towards the Microbial Sciences secondary field and one towards their concentration, or they may count the second semester as one of their two 100-level electives in the secondary field. A single semester of Life Sciences 100r may not be double-counted. 
  • Courses from study abroad, Harvard Summer School, or MIT could count toward secondary field credit if approved by MSI. Approval must be obtained prior to the student's enrollment in these courses to be guaranteed. The petitioning student must provide a syllabus or detailed course summary to MSI for review. A petition to retroactively consider substituting one relevant Freshman Seminar for one of the two 100-level elective courses also will be considered. 


The MSI secondary totals five courses (20 credits) in three categories.

  • Requirement 1: The two MSI cornerstone courses.

  • Requirement 2: One introductory course. 

  • Requirement 3: Two additional microbial courses at the 100-level or above.

Click HERE to learn more about the courses that fulfull these requirements.

Note that students are also strongly encouraged to play an active role in the MSI community by attending additional MSI programming, including weekly chalk talks, monthly seminars, and the annual symposium. If conducting research, students are also invited to apply for the MSI Summer Undergraduate Fellowship, which (if awarded) provides a stipend to support the student conducting research with an MSI faculty affiliate over a 10-week summer period. 


Application Instructions

  • Students interested in pursuing a secondary field in Microbial Sciences should initiate contact with MSI leadership using the MSI email address MSI(at)fas(dot)harvard(dot)edu.
  • Students will submit an application to MSI for the secondary field no later than the course enrollment due date of their penultimate term.  
  • Additionally, students must file online with the Registrar's Office through the Secondary Fields Web Tool.